U.S. patent application number 15/422444 was filed with the patent office on 2017-05-25 for apparatus and method for stabilizing adjacent bone portions.
The applicant listed for this patent is Fran Korhonen, Jason Sandstrom, Matthew N. Songer. Invention is credited to Fran Korhonen, Jason Sandstrom, Matthew N. Songer.
Application Number | 20170143513 15/422444 |
Document ID | / |
Family ID | 52006082 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170143513 |
Kind Code |
A1 |
Sandstrom; Jason ; et
al. |
May 25, 2017 |
APPARATUS AND METHOD FOR STABILIZING ADJACENT BONE PORTIONS
Abstract
Instruments, kits, and methods are disclosed for installing an
implant spacer through an incision and down a surgical corridor.
The instruments also serve to align a drill guide and align and
insert a spacer stabilizer for stabilization of adjacent bone
portions. The instrument comprises an elongated guide bar body, an
inserter face at a distal end of said guide bar body for abutting
an instrument attachment portion of a spacer, a connection tip
portion for securing a spacer against an inserter face, and a guide
portion of said elongated guide bar body for aligning instruments
with said spacer and for introducing a stabilizer to secure the
spacer in a predetermined position between the bone portions.
Included is a retractable graft block for securing graft material
within an aperture of said spacer during insertion of the
spacer.
Inventors: |
Sandstrom; Jason;
(Marquette, MI) ; Korhonen; Fran; (Negaunee,
MI) ; Songer; Matthew N.; (Marquette, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sandstrom; Jason
Korhonen; Fran
Songer; Matthew N. |
Marquette
Negaunee
Marquette |
MI
MI
MI |
US
US
US |
|
|
Family ID: |
52006082 |
Appl. No.: |
15/422444 |
Filed: |
February 1, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14453520 |
Aug 6, 2014 |
9592131 |
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15422444 |
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13347526 |
Jan 10, 2012 |
9486324 |
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14453520 |
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12692503 |
Jan 22, 2010 |
8157865 |
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13347526 |
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61862671 |
Aug 6, 2013 |
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61431235 |
Jan 10, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2002/2835 20130101;
A61F 2/4611 20130101; A61F 2002/30182 20130101; A61F 2002/30392
20130101; A61F 2002/30401 20130101; A61F 2002/30518 20130101; A61F
2002/3037 20130101; A61F 2310/00023 20130101; A61F 2310/00179
20130101; A61F 2002/30133 20130101; A61F 2002/30387 20130101; A61F
2002/305 20130101; A61F 2002/30395 20130101; A61F 2002/30883
20130101; A61F 2002/30197 20130101; A61F 2002/30616 20130101; A61F
2002/30136 20130101; A61F 2310/00017 20130101; A61F 2002/30164
20130101; A61F 2002/30331 20130101; A61F 2002/30166 20130101; A61F
2002/30892 20130101; A61F 2310/00359 20130101; A61F 2/30767
20130101; A61F 2/4465 20130101; A61F 2002/30884 20130101; A61F
2002/30172 20130101; A61F 2002/30507 20130101; A61B 17/1757
20130101; A61F 2002/30904 20130101; A61F 2002/30593 20130101; A61F
2002/30594 20130101; A61F 2/4455 20130101 |
International
Class: |
A61F 2/46 20060101
A61F002/46; A61F 2/30 20060101 A61F002/30; A61F 2/44 20060101
A61F002/44 |
Claims
1. A method of implanting a spacer implant within an intervertebral
space and fixing with a stabilizer implant comprising the steps of:
selecting an intervertebral spacer of a predetermined size for
seating in an intervertebral space having an anchor portion
comprising one or more channels extending from a proximal end;
securing a spacer inserter tool to a proximal end of said
intervertebral spacer with said anchor portion channel of said
intervertebral spacer aligned with a spacer inserter channel on
said spacer inserter tool; advancing said intervertebral spacer
using said spacer inserter tool through a prepared incision until
seated in an intervertebral space; inserting and distally advancing
a tip of a drill guide into one of said spacer inserter channels on
said spacer inserter tool for assuring correct drill position with
respect to said intervertebral spacer; selecting a bone drill of
predetermined diameter; advancing said drill into a cylinder of
said drill guide and creating a bore of a predetermined depth
through a wall of a corresponding vertebral body; removing said
drill and said drill guide; selecting a first stabilizer implant;
securing a stabilizer inserter to said first stabilizer implant;
inserting a base wall of said first stabilizer implant into a
spacer inserter channel on said spacer inserter tool and advancing
said base wall whereby said stabilizer implant occupies the drilled
vertebral body bore; removing said stabilizer inserter from said
first stabilizer implant; reinserting and fully advancing said
drill guide into and along said spacer inserter channel on said
spacer inserter tool; securing a threaded spreader to a spreader
driver; advancing said spreader driver and threaded spreader down a
drill guide cylinder of said drill guide and into a central bore of
said first stabilizer implant; and removing said spreader driver
and said drill guide.
2. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant further
comprising the step of repeating on an opposing side of said
intervertebral spacer the steps required to insert said first
stabilizer and said first spreader for a second stabilizer and a
second spreader.
3. The method of claim 2 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of selecting an intervertebral spacer of a predetermined
size for seating in an intervertebral space having an anchor
portion comprising one or more channels extending from a proximal
end further comprises the step of: selecting a spacer wherein said
one or more channels are in the form of opposing T-slots with a
first T-slot opening towards a first opposing surface on said
spacer facing a first vertebral body and with a second T-slot
opening towards a second opposing surface on said spacer facing a
second vertebral body.
4. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
preceding the step of advancing said intervertebral spacer using
said spacer inserter tool through a prepared incision until seated
in an intervertebral space further comprises the steps of: choosing
a first graft block and aligning and inserting a channel lock of
said first graft block into said spacer inserter channel on said
spacer inserter tool and advancing said first graft block distally
until a containing face of said first graft block covers a spacer
graft opening of said intervertebral spacer implant.
5. The method of claim 4 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant further
comprising the step of: packing a graft opening in said
intervertebral spacer implant with one or more of bone graft and
bone graft substitute preceding the step of advancing said
intervertebral spacer using said spacer inserter tool through a
prepared incision until seated in an intervertebral space.
6. The method of claim 5 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant further
comprising the steps of: inserting and advancing a second channel
lock of a second graft block into a second spacer inserter channel
thereby fully enclosing bone graft substitute within a graft
opening of said intervertebral spacer following the step of packing
a graft opening of said intervertebral spacer implant with one or
more of bone graft and bone graft substitute.
7. The method of claim 6 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of advancing said intervertebral spacer using said spacer
inserter tool through a prepared incision until seated in an
intervertebral space causes a consequent forcing of one or more of
said first graft block and second graft block proximally.
8. The method of claim 7 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant further
comprising the step of fully removing said graft block prior to the
step of inserting a drill guide.
9. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of advancing said intervertebral spacer using said spacer
inserter tool through a prepared incision until seated in an
intervertebral space is preceded by and further comprises the step
of using a tissue retractor to create a surgical corridor to the
intervertebral space.
10. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of advancing said drill into a cylinder of said drill
guide and creating a bore into a wall of corresponding vertebral
body further comprises the step of: advancing said drill until a
drill stop on said drill abuts a drill guide shoulder indicating
said drill has reached a predetermined depth suitable for seating
said first stabilizer implant.
11. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a first stabilizer implant
wherein the step of inserting a base wall of said stabilizer
implant into a spacer inserter channel on said spacer inserter tool
and advancing said base wall into an aligned intervertebral spacer
channel of said intervertebral spacer using said stabilizer
inserter wherein said stabilizer implant occupies said vertebral
body bore further comprises the step of: advancing said stabilizer
into the created vertebral bore until said stabilizer abuts a
stabilizer stop in said intervertebral spacer.
12. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a first stabilizer implant
wherein the step of inserting a base wall of said stabilizer
implant into a spacer inserter channel on said spacer inserter tool
and advancing said base wall into an aligned intervertebral spacer
channel of said intervertebral spacer using said stabilizer
inserter and wherein said stabilizer implant occupies said
vertebral body bore further comprises the step of: advancing said
stabilizer into the created vertebral bore and utilizing a web wall
of a stabilizer implant having a sharp leading edge to cut through
a cortical bone wall of a vertebral body.
13. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of advancing said spreader driver and threaded spreader
down a drill guide cylinder into a central bore of said stabilizer
further comprises the step of: fully seating said threaded spreader
within said stabilizer causing consequent spreading of said
stabilizer's repositionable body tabs into surrounding bone.
14. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of inserting and advancing a tip of a drill guide into one
of said spacer inserter channels on said spacer inserter tool
assuring correct drill position with respect to said intervertebral
spacer further comprises the step of: engaging said drill guide tip
within an aligned intervertebral spacer channel of said
intervertebral spacer.
15. The method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step inserting a base wall of said stabilizer implant into a
spacer inserter channel on said spacer inserter tool and advancing
said base wall whereby said stabilizer implant occupies said
vertebral body bore further comprises the step of: engaging said
base wall of said stabilizer implant into an aligned intervertebral
spacer channel of said intervertebral spacer using said stabilizer
inserter.
16. The method of claim 15 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant further
comprising the step of: advancing said base wall within a spacer
inserter channel wherein one or more self-retaining clips extends
into an undercut region of said spacer inserter channel to prevent
unintentional back out of said stabilizer implant from said spacer
implant.
17. The method of claim 15 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant further
comprising the step of: advancing said base wall within a spacer
inserter channel wherein one or more self-retaining clips becomes
blocked by a blocking surface to block said stabilizer from backing
out.
18. A method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of securing a spacer inserter tool to a proximal end of
said intervertebral spacer with said anchor portion channel of said
intervertebral spacer aligned with a spacer inserter channel on
said spacer inserter tool further comprises the step of: aligning
and inserting a first prong of a connection tip portion of said
spacer inserter tool in a first attachment hole at a proximal end
of said intervertebral spacer implant.
19. A method of claim 1 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of securing a spacer inserter tool to a proximal end of
said intervertebral spacer with said anchor portion channel of said
intervertebral spacer aligned with a spacer inserter channel on
said spacer inserter tool further comprises the step of: advancing
a locking shaft having a threaded prong of a connection tip portion
of said spacer inserter tool in a threaded attachment hole at a
proximal end of said intervertebral spacer implant wherein an
inserter face of spacer inserter tool is fixed against a proximal
face of said spacer.
20. A method of claim 19 of implanting a spacer implant within an
intervertebral space and fixing with a stabilizer implant wherein
the step of aligning and advancing a locking shaft having a
threaded prong of a connection tip portion of said spacer inserter
tool in a threaded attachment hole at a proximal end of said
intervertebral spacer implant wherein an inserter face is fixed
against a proximal face of said spacer further comprises the step
of: applying a torsional force to a threaded spool located at a
proximal end of said locking shaft.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a U.S. Divisional patent application of
Continuation-In-Part patent application Ser. No. 14/453,520 filed
Aug. 6, 2014 which claims priority to Continuation-In-Part patent
application Ser. No. 13/347,526 filed Jan. 10, 2012, now U.S. Pat.
No. 9,486,324, which claims priority to Continuation-In-Part
application Ser. No. 12/692,503 filed on Jan. 22, 2010, now U.S.
Pat. No. 8,157,865. Application Ser. No. 13/347,526 claims benefit
of provisional application No. 61/431,235 filed on Jan. 10, 2011
and application Ser. No. 14/453,520 claims benefit of provisional
patent application No. 61/862,671 filed Aug. 6, 2013, the entire
disclosures of which are hereby incorporated by reference and
relied upon.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] The present invention relates generally to the stabilization
of adjacent bone portions, and more particularly to an apparatus
for securing interbody spacers between the adjacent bone portions
and related instruments. The invention is also directed to a method
for stabilizing the adjacent bone portions.
[0004] Description of Related Art
[0005] Many different medical procedures are performed that require
the stabilization of adjacent bone portions through the securing of
an interbody spacer to the adjacent bone portions. Examples of
these spacers are those known in the field as interbody cages,
corpectomy cages, osteotomy wedges, joint spacers, bone void
fillers, etc.
[0006] As one example, spacers are used to fuse joints. Spacers are
also used to repair complex fractures where bone is missing and in
bone regions where there are otherwise voids, as when a tumor and
adjacent bone are removed. Spacers are also used in the performance
of osteotomies by placing the spacers between adjacent bone
portions to perform a wedging action, as to straighten a bone. This
list is not exhaustive of the medical procedures that require the
placement of a spacer between adjacent bone portions.
[0007] In each procedure, the spacer placed between the bone
portions is required to be rigidly joined to the adjacent bone
portions. A multitude of different apparatus have been devised for
this purpose, with many requiring the insertion of screws. While
screws are generally effective for this purpose, they are limited
in the sense that they do not afford stability in all dimensions
required to effect the optimal or desired rigidity.
[0008] Spacers are commonly used in spinal repair and
reconstruction. The spine is a flexible column formed of a
plurality of bones called vertebrae. The vertebrae are hollow and
piled one upon the other, forming a strong hollow column for
support of the cranium and trunk. The hollow core of the spine
houses and protects the nerves of the spinal cord. The different
vertebrae are connected to one another by means of articular
processes and intervertebral, fibrocartilaginous bodies.
[0009] The intervertebral fibro-cartilages are also known as
intervertebral disks and are made of a fibrous ring filled with
pulpy material. The disks function as spinal shock absorbers and
also cooperate with synovial joints to facilitate movement and
maintain flexibility of the spine. When one or more disks
degenerate through accident or disease, nerves passing near the
affected area may be compressed and are consequently irritated. The
result may be chronic and/or debilitating back pain. Various
methods and apparatus have been designed to relieve such back pain,
including spinal fusion using a suitable graft or interbody spacer
using techniques such as Anterior Lumbar Interbody Fusion (ALIF),
Posterior Lumbar Interbody Fusion (PLIF), or Transforaminal Lumbar
Interbody Fusion (TLIF) surgical techniques. The implants used in
these techniques, also commonly referred to as vertebral body
replacement (VBR) devices, are placed in the interdiscal space
between adjacent vertebrae of the spine.
[0010] Ideally, a fusion graft should stabilize the intervertebral
space and become fused to adjacent vertebrae. Moreover, during the
time it takes for fusion to occur, the graft should have sufficient
structural integrity to withstand the stress of maintaining the
space without substantially degrading or deforming and have
sufficient stability to remain securely in place prior to actual
bone ingrowth fusion.
[0011] One significant challenge to providing fusion graft
stability (prior to actual bone ingrowth fusion) is preventing
spinal extension during patient movement. Distraction of the
vertebral space containing the fusion graft may cause the graft to
shift or move, disrupting bone ingrowth fusion and causing
pain.
[0012] Generally, existing spinal fusion technology has been
limited or lacking in certain respects. Among the limitations of
certain of these systems is the requirement that complicated steps
be performed to effect their use. Others of these systems lack the
optimal multidimensional stability, while others are less than
desirable because they utilize components that project to
externally of one or more of the bone portions between which the
spacer is located.
[0013] The systems that rely upon the use of screws normally have
such limitations. Generally these systems do not effectively allow
compression forces to be generated between the spacers and adjacent
bone portions. Further, while the screws stabilize the bone-spacer
junction in one plane, that is normally flexion-extension, they do
not control bending in planes orthogonal to the plane of the screw,
that is normally side-to-side bending.
[0014] A further problem with existing systems is that parts
typically are not locked and are thus prone to working loose.
Screws, for example, may loosen over time in the absence of
incorporating some structure that effectively prevents turning or
lengthwise movement that results in partial or full separation from
the bone portions and/or spacers that they penetrate.
[0015] The spacers and features of the spacer for joining it to the
bone portions are typically inserted within surgical corridors
offering limited access and vision. A further problem is that
existing systems do not have instrumentation that is intuitive and
well suited for performing the surgical procedure within this
corridor. Instruments that are not intuitive make the surgery
difficult and increases the potential for injury to the
patient.
[0016] The medical field is constantly seeking system designs that
might be efficiently and consistently installed and that, most
significantly, will effect the desired fusion in a manner that will
be safe and reliable for the patient.
BRIEF SUMMARY OF THE INVENTION
[0017] In one form, the invention is directed to a method for
stabilizing first and second adjacent bone portions. The method
includes the steps of: providing a spacer; providing a stabilizer,
with the spacer and stabilizer configured to be movable guidingly,
one relative to the other, between a pre-assembly relationship and
an operative relationship; and placing the spacer and stabilizer
into an operative relationship with the first and second adjacent
bone portions by: a) placing the spacer between the first and
second adjacent bone portions; b) directing the stabilizer into the
first bone portion; and c) changing the spacer and stabilizer from
their preassembly relationship into their operative relationship.
As an incident of the spacer and stabilizer being changed from
their pre-assembly relationship into the operative relationship
with each other and the first and second bone portions, the spacer,
stabilizer and first bone portion cooperate to cause the first bone
portion and spacer to be urged towards each other.
[0018] In one form, the step of providing a stabilizer involves
providing a stabilizer with a body having first and second spaced
walls joined by a web. The first and second spaced walls
respectively have first and second surfaces that face each
other.
[0019] In one form, the method further includes the step of
pre-forming a first channel in the first bone portion and the step
of directing the stabilizer into the first bone portion involves
moving the second wall guidingly in the first channel between a
first position and a second position. The second wall is in the
second position with the spacer and stabilizer in the operative
relationship with the first and second adjacent bone portions.
[0020] In one form, the spacer has a first surface that faces a
first surface on the first bone portion with the spacer between the
first and second bone portions and the stabilizer web has a sharp
leading edge. The step of directing the stabilizer into the first
bone portion includes the step of causing the sharp leading edge on
the web to cut through the first bone portion between the first
channel and first surface on the first bone portion.
[0021] In one form, the step of providing a stabilizer involves
providing a stabilizer having a length, with the second wall having
a lengthwise axis. The second surface has a convex curvature, as
seen in cross-section taken transversely to the length of the
stabilizer, with a radius at or adjacent to the lengthwise axis of
the second wall. The stabilizer further has a leading end and a
nose with a tapered surface portion that is angled between the
leading end and the second surface. The spacer is placed between
the first and second bone portions before the stabilizer is
directed into the first bone portion. As an incident of the
stabilizer being changed from its first position into its second
position, the tapered nose surface bears against the first bone
portion and progressively wedges the first bone portion towards the
spacer.
[0022] In one form, the first and second bone portions are adjacent
first and second vertebrae. The spacer has oppositely facing first
and second surfaces. The first vertebra has a first endplate with a
first surface facing the first surface on the spacer. The first
endplate has a first dimension parallel to the length of the
stabilizer with the spacer and stabilizer in their operative
relationship. The step of providing a stabilizer involves providing
a stabilizer wherein the second surface on the stabilizer applies a
force on the first bone portion over a majority of the first
dimension of the first surface of the first endplate that urges the
first endplate surface against the first spacer surface.
[0023] In one form, the step of placing the spacer and stabilizer
into operative relationship with the first and second adjacent bone
portions involves causing a part of the first bone portion and a
part of the spacer to be compressively maintained between the first
and second stabilizer surfaces.
[0024] In one form, the step of directing the stabilizer into the
first bone portion involves advancing the stabilizer guidingly in a
path in a first direction, The method further includes the step of
reconfiguring the stabilizer, with the spacer and stabilizer in the
operative relationship with the first and second adjacent bone
portions, into a locked state to block movement of the stabilizer
relative to the first bone portion oppositely to the first
direction.
[0025] In one form, the stabilizer has a first tab and the step of
reconfiguring the stabilizer from the first state into the locked
state involves moving the first tab from a first position into a
second position wherein the first tab bears against the first bone
portion.
[0026] In one form, the step of providing a stabilizer involves
providing a stabilizer with a movable spreader, and the step of
reconfiguring the stabilizer involves moving the spreader from a
first position into a second position as an incident of which the
first tab is moved from its first position into its second
position.
[0027] In one form, the step of providing a stabilizer involves
providing a stabilizer that is turned about an axis relative to the
second wall to change the spreader between its first and second
positions.
[0028] In one form, the first tab has a hinge portion and the step
of moving the tab involves moving the tab about the hinge portion
from its first position into its second position.
[0029] In one form, the first tab has a live hinge and the step of
moving the first tab involves moving the tab about the live hinge
portion from its first position into its second position.
[0030] In one form, the step of providing a stabilizer involves
providing a stabilizer with first and second movable tabs, and the
step of reconfiguring the stabilizer from the first state into the
locked state involves moving the first tab from a first position
into a second position wherein the first tab bears against the
first bone portion. The second tab defines the tapered nose surface
portion.
[0031] In one form, the step of providing a stabilizer involves
providing a stabilizer with a movable spreader, and the step of
reconfiguring the stabilizer involves moving the spreader from a
first position into a second position, as an incident of which the
first tab is moved from its first position into its second position
and the second tab is moved from a first position into a second
position.
[0032] In one form, the step of moving the spreader involves moving
the spreader from its first position into its second position and
against each of the first and second tabs to change each of the
first and second tabs from its first position into its second
position.
[0033] In one form, the step of providing a spacer involves
providing a spacer with a channel and the step of changing the
spacer and stabilizer from their pre-assembly relationship into
their operative relationship involves moving a part of the
stabilizer guidingly within the channel.
[0034] In one form, the steps of providing a spacer and stabilizer
involve providing a spacer and stabilizer each with a blocking
surface, which blocking surfaces abut to block the spacer and
stabilizer from moving out of their operative relationship.
[0035] In one form, the steps of providing a spacer and stabilizer
involve providing a spacer and stabilizer each with a blocking
surface, which blocking surfaces are brought into confronting
relationship as an incident of the spacer and stabilizer being
changed from their pre-assembly relationship into their operative
relationship.
[0036] In one form, the method further includes the step of
reconfiguring one of the spacer and stabilizer with the spacer and
stabilizer in their operative relationship to thereby place the
blocking surfaces on each of the spacer and stabilizer in
confronting relationship.
[0037] In one form, the steps of providing a spacer and stabilizer
involve providing a deflectable tab defining the blocking surface
on one of the spacer and stabilizer which deflects in one direction
as the spacer and stabilizer are changed from their pre-assembly
relationship into their operative relationship and is moved
oppositely to the one direction under a restoring force to place
the blocking surface on the one of the spacer and stabilizer into
confronting relationship with the blocking surface on the other of
the spacer and stabilizer as an incident of the spacer and
stabilizer realizing the operative relationship.
[0038] In one form, the step of providing a stabilizer involves
providing a stabilizer wherein the deflectable tab is on the first
wall of the stabilizer.
[0039] In one form, the step of providing a stabilizer involves
providing a stabilizer wherein the first wall and web on the
stabilizer cooperatively define a "T"-shaped portion.
[0040] In one form, the step of providing a spacer involves
providing a spacer with a "T"-shaped channel that is complementary
to the "T"-shaped portion of the stabilizer, and the step of
changing the spacer and stabilizer from their pre-assembly
relationship into their operative relationship involves moving the
"T"-shaped portion of the stabilizer guidingly within the
"T"-shaped channel.
[0041] In one form, the step of providing a stabilizer involves
providing a stabilizer with the second surface on the second wall
having a convexly curved shape.
[0042] In one form, the step of providing a stabilizer involves
providing a stabilizer with the second wall on the stabilizer
having a cylindrical shape.
[0043] In one form, the step of providing a stabilizer involves
providing a stabilizer wherein the first wall and web are
substantially flat and cooperatively define a "T"-shaped portion.
The second surface on the second wall has a convexly curved
shape.
[0044] In one form, the method further involves the step of
reconfiguring the stabilizer from a first state, with the spacer
and stabilizer in the operative relationship with the first and
second adjacent bone portions, into a locked state by moving a part
of the stabilizer forcibly against the first bone portion.
[0045] In one form, the stabilizer is directed into the bone
portion before the spacer and stabilizer are changed from their
pre-assembly relationship into their operative relationship.
[0046] In one form, the method further includes the step of
providing a second stabilizer and connecting the second stabilizer
to each of the spacer and the second bone portion.
[0047] In one form, the method further includes the step of
reconfiguring the stabilizer after it has been changed into the
locked state back into the first state and thereafter separating
the stabilizer and spacer from the first and second bone
portions.
[0048] In one form, the method further includes the steps of
providing a guide structure on the spacer and using the guide
structure to pre-form the first channel in the first bone
portion.
[0049] In one form, the step of moving the part of the stabilizer
forcibly against the first bone portion involves the step of moving
the part of the stabilizer forcibly against the first bone portion
in a manner so as to thereby urge the first bone portion and spacer
against each other.
[0050] In one form, the step of providing a spacer involves
providing a spacer with first and second spaced bores. The method
further includes the step of providing an auxiliary tool that is
used in conjunction with the spacer by connecting the auxiliary
tool using at least one of the first and second bores.
[0051] In one form, the method further includes the step of
connecting the auxiliary tool to the spacer by placing first and
second connectors on the auxiliary tool one each into the first and
second bores.
[0052] In one form, the method further includes the step of
connecting the auxiliary tool to the spacer by using either one,
but only one, of the first and second bores.
[0053] In one form, the steps of providing a spacer and stabilizer
include providing first and second deflectable tabs each defining a
blocking surface on at least one of the spacer and stabilizer that
each deflects in a direction as the spacer and stabilizer are
changed from the preassembly relationship into the operative
relationship, and are moved oppositely to their deflecting
direction under restoring forces to place each of the blocking
surfaces separately into confronting relationship with a blocking
surface on the spacer or stabilizer as an incident of the spacer
and stabilizer realizing the operative relationship.
[0054] In one form, the step of placing a spacer and stabilizer in
operative relationship with the first and second bone portions
involves moving the spacer and stabilizer substantially only in a
single plane and parallel to a single line.
[0055] In one form, the step of preparing the spacer with graft
includes covering bone graft in a graft aperture within the spacer
to prevent unintentional fallout of the bone graft while packing
bone graft in the spacer aperture and during insertion of the
spacer between bone portions.
[0056] In one form, the step of preparing the spacer with graft
includes inserting a graft block into an anchor portion of the
spacer wherein a paddle extending from the graft block covers a
graft aperture on the spacer to prevent unintentional fallout of
bone graft packed within the graft aperture.
[0057] In one form, the step of preparing the spacer with graft
includes inserting a plurality of graft blocks into one or more
anchor portions of the spacer wherein a plurality of paddles on the
graft blocks cause the bone graft to be fully encapsulate the bone
graft within the graft aperture.
[0058] In one form, during the step of inserting the spacer between
the bone portions, the graft blocks are retracted therein placing
the spacer's graft aperture in direct communication with the bone
portions.
[0059] In one form, the step of inserting the spacer between the
bone portions includes abutting a stop face on the graft block
against the bone portions preventing further advancement of the
graft block.
[0060] In one form, the step of inserting the spacer between the
bone portions includes the step of one or more graft blocks
retracted from the incision site.
[0061] In one form, the step of inserting a drill guide includes
joining the tip of a drill guide with an anchor portion of a spacer
and advancing the drill guide to a predetermined position against a
bone portion.
[0062] In one form, the step of creating a hole within a bone
portion includes advancing a bone drill down a drill guide and into
the bone portion.
[0063] In one form, the step of inserting a stabilizer includes
releasably securing a stabilizer inserter to a proximal end of a
stabilizer.
[0064] In one form, the step of inserting a stabilizer includes
aligning a base wall nose within a spacer channel or spacer
inserter tool channel and advancing the stabilizer into the spacer
by applying directed force to a stabilizer inserter.
[0065] In one form, the step of inserting a stabilizer includes
advancing the stabilizer until the stabilizer reaches a
predetermined position with respect to the spacer and locking the
stabilizer in place. In one form, the step of inserting a
stabilizer includes removing a stabilizer inserter from the
incision site.
[0066] In one form, the step of placing the stabilizer in an
operative relationship includes inserting the tip of a drill guide
into a spacer channel or spacer inserter channel and advancing the
drill guide to the stabilizer.
[0067] In one form, the step of placing the stabilizer in an
operative relationship includes releasably securing a spreader
driver tool to a spreader and advancing the spreader into the
stabilizer.
[0068] In one form, the invention is directed to the combination of
a stabilizer and spacer. The spacer can be placed between first and
second adjacent bone portions and has oppositely facing surfaces.
The stabilizer is movable guidingly relative to the spacer in a
first path in a first direction: a) from a position wherein the
stabilizer is in a pre-assembly relationship with the spacer; and
b) into a position wherein the stabilizer is in an operative
relationship with the spacer. The stabilizer is capable of being
directed in the first direction while being moved in the first path
relative to the spacer into one of the first and second bone
portions so as to urge a surface of the one bone portion forcibly
against one of the spacer surfaces with the spacer and stabilizer
in operative relationship with each other and the first and second
adjacent bone portions. The stabilizer has a body including first
and second spaced walls joined by a web. The first and second
spaced walls respectively have first and second surfaces that face
each other. The second wall has a leading end and a surface portion
that is angled with respect to the first path to produce a wedging
action against the one bone portion as the stabilizer is advanced
in the first direction in the first path into the one bone portion.
The wedging action causes a part of the one bone portion and a part
of the spacer to be urged towards each other as the spacer and
stabilizer are moved into operative relationship with each other
and the first and second adjacent bone portions.
[0069] In one form, the stabilizer has a length and a lengthwise
axis. The first path is substantially straight along a first line
and the second surface has a convex curvature as seen in
cross-section taken transverse to the length of the stabilizer with
a radius that is centered on a line parallel to the lengthwise axis
of the stabilizer.
[0070] In one form, the stabilizer has a nose defining the tapered
surface portion that is angled with respect to the central axis of
the stabilizer.
[0071] In one form, the second wall has a cylindrical shape and the
nose defines the surface portion that tapers between a leading end
of the second wall and the second surface.
[0072] In one form, the nose is split to define separate tabs. One
of the tabs is selectively movable so that the one tab forcibly
engages the one bone portion to change the stabilizer from a first
state into a locked state to prevent movement of the stabilizer
relative to the one bone portion with the spacer and stabilizer in
operative relationship with each other and the first and second
adjacent bone portions.
[0073] In one form, the combination further includes a spreader
that is selectively movable relative to the stabilizer to thereby
change the stabilizer from the first state into the locked
state.
[0074] In one form, the first wall and web are substantially flat
and cooperatively define a "T"-shaped portion. The spacer has a
"T"-shaped channel that cooperates with the "T"-shaped portion of
the stabilizer to guide relative movement between the pre-assembly
and operative relationships.
[0075] In one form, the second wall has a substantially cylindrical
shape that defines the second surface.
[0076] In one form, the first surface resides in a first plane and
the cylindrical shape has a central axis. The first plane and
central axis of the cylindrical shape are substantially
parallel.
[0077] In one form, the first surface resides in a first plane and
the cylindrical shape has a central axis and the first plane and
central axis of the cylindrical shape are at an angle with respect
to each other.
[0078] In one form, the spacer has a channel to guide the
stabilizer as the spacer and stabilizer are relatively moved
between their pre-assembly and operative relationships. The spacer
has a stop portion that abuts the stabilizer moving in the first
direction so that the spacer and stabilizer can be consistently
placed in their operative relationship.
[0079] In one form, the spacer and stabilizer have cooperating
blocking surfaces that abut to block the spacer and stabilizer from
moving out of their operative relationship.
[0080] In one form, the blocking surfaces contact each other as an
incident of the spacer and stabilizer realizing the assembly
relationship.
[0081] In one form, one of the blocking surfaces is on a movable
tab on one of the spacer and stabilizer. The movable tab is
deflected in one direction as the spacer and stabilizer are moved
from their pre-assembly relationship toward their operative
relationship and moves under a restoring force oppositely to the
one direction upon the operative relationship between the spacer
and stabilizer being realized.
[0082] In one form, the second wall has a cylindrical shape with a
central axis. The combination further includes a drill guide on the
spacer and a drill that is movable controllably along the drill
guide parallel to a central axis of the drill. The spacer has a
third surface to which the first surface of the stabilizer abuts
with the spacer and stabilizer in their operative relationship. A
first distance between the central axis of the drill on the drill
guide and the third surface is greater than a second distance
between the central axis of the second wall and the first
surface.
[0083] In one form, the first distance is greater than the second
distance by on the order of 0.5 mm.
[0084] In one form an auxiliary tool is a cage or spacer inserter
tool.
[0085] In one form, the spacer inserter tool comprises a
longitudinal guide to direct the stabilizer through an incision and
into an anchor portion of the spacer. In one form the longitudinal
guide directs axillary tools into or in alignment with an anchor
portion of the spacer.
[0086] In one form, the longitudinal guide comprises opposing
channels.
[0087] In one form, the opposing channels are in the form of
T-shaped slots.
[0088] In one form, the body of the spacer inserter tool comprises
a shaft aperture.
[0089] In one form, the spacer inserter tool houses a locking shaft
for securing the spacer to the spacer inserter tool.
[0090] In one form, the locking shaft resides in an shaft aperture
having an elongate axis formed within the spacer inserter tool.
[0091] In one form, the elongate axis of the shaft aperture formed
within the spacer inserter tool for housing the locking shaft is
parallel to an elongate axis of the longitudinal guide.
[0092] In one form, the spacer inserter tool comprises a handle
portion for grasping by the user for controlling the spacer
inserter tool.
[0093] In one form, an elongate axis of the handle portion is
generally perpendicular to an elongate axis of a guide bar body
portion of the spacer inserter tool.
[0094] In one form, the locking shaft includes an impact fitting.
The impact fitting may be used to tap the spacer inserter and
spacer into the intervertebral space.
[0095] In one form, an auxiliary tool is a graft blocker for
containing bone graft or bone substitute within the spacer during
insertion of the spacer.
[0096] In one form the graft blocker comprises a paddle portion for
covering an opening within the spacer where graft is contained
during implant insertion.
[0097] In one form, the graft blocker comprises one or more channel
locks for guiding and sliding engagement of the graft blocker with
the longitudinal guide of the spacer inserter tool and for sliding
engagement with an aligned anchor portion within the spacer.
[0098] In one form, the graft blocker includes an arm for the user
to control the graft blocker from outside the incision while the
spacer is inserted to a predetermined position between the bone
portions.
[0099] In one form, the graft blocker includes a stop face that
abuts the bone portions and causes retraction of the graft blocker
as the spacer is inserted between the bone portions.
[0100] In one form, the auxiliary instruments comprise cleaning or
access apertures for cleaning the instruments.
[0101] In one form, the auxiliary instrument is a drill guide for
guiding a drill to predetermined location within a bone
portion.
[0102] In one form, the drill guide includes a drill guide cylinder
for guiding a drill within the drill guide.
[0103] In one form, the drill guide comprises a drill guide tip
that is insertable into an anchor portion of a spacer to ease
insertion of the drill guide into the spacer.
[0104] In one form, the drill guide includes a handle portion for
the user to control position of the drill guide within the
incision.
[0105] In one form, the drill guide includes a base wall and a web
wall for aligning the drill guide within the longitudinal guide of
the spacer inserter tool or within the anchor portion of the
spacer.
[0106] In one form, the drill guide includes a drill guide stop to
align the relative depth of drill guide with the spacer inserter
tool.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0107] These and other features and advantages of the present
invention will become more readily appreciated when considered in
connection with the following detailed description and appended
drawings, wherein:
[0108] FIG. 1 is a schematic, perspective view of one embodiment of
an interbody spacer showing a superior surface and an anterior
surface thereof;
[0109] FIG. 2 is a perspective view of one embodiment of a
stabilizer;
[0110] FIG. 3 is an end view of the stabilizer of FIG. 2;
[0111] FIG. 4 is an end plan view of the spacer of FIG. 1 inserted
between two vertebrae with the stabilizers of FIG. 2 anchoring the
spacer to the vertebrae;
[0112] FIG. 5A is a top perspective view of another embodiment of a
stabilizer;
[0113] FIG. 5B is an end view of the stabilizer of FIG. 5A;
[0114] FIGS. 6A-6J depict end views of multiple embodiments of
different stabilizers;
[0115] FIG. 7 is an end view of one embodiment of a spacer with
self-retaining clips;
[0116] FIGS. 8A-M depict various conventional embodiments of
interbody spacers;
[0117] FIG. 9 is a schematic, perspective view of another
embodiment of an interbody spacer showing a superior surface and an
anterior surface thereof;
[0118] FIG. 10 is an end view of yet another embodiment of a
stabilizer;
[0119] FIG. 11 is a perspective view of the stabilizer of FIG.
10;
[0120] FIG. 12 is an end view of the spacer of FIG. 9 with the two
stabilizers according to FIG. 10 inserted into the spacer;
[0121] FIG. 13 is a schematic representation of an inventive
system, including at least one bone portion/member with an
interbody spacer fixed thereagainst utilizing a stabilizer;
[0122] FIG. 14 is a perspective view of a modified form of
stabilizer, according to the invention;
[0123] FIG. 15 is a fragmentary, perspective view showing a spacer
against a bone portion and a further modified form of stabilizer
that is configured to urge the bone portion and spacer towards each
other as the stabilizer is inserted;
[0124] FIG. 16 is a view as in FIG. 15 wherein a different
configuration of stabilizer and spacer are used to perform as
described for the corresponding components in FIG. 16;
[0125] FIG. 17 is a view as in FIGS. 15 and 16 showing a further
modified form of stabilizer with one form of locking assembly to
maintain the stabilizer in place;
[0126] FIG. 18 is an enlarged, plan view of a modified form of
locking assembly on a stabilizer and spacer and with locking
assembly components on the stabilizer configured as they would be
with the locking assembly in a locked state;
[0127] FIG. 19 is a perspective view of a modified form of
stabilizer and spacer, similar to that shown in FIG. 18, with a
locking assembly thereon in an assembly state, the stabilizer
aligned to be directed into the spacer and abutted bone portion and
with a spreader element aligned to be directed into the stabilizer
to change the locking assembly from the assembly state into a
locked state;
[0128] FIG. 20 is an enlarged, fragmentary, plan view of the
stabilizer in FIG. 19 with the locking assembly component on the
stabilizer shown in solid lines as it is configured with the
locking assembly in an assembly state and in dotted lines as it is
configured with the locking assembly in the locked state;
[0129] FIG. 21 is an elevation view of a modified form of
stabilizer joined with a spacer and bone portion with a locking tab
secured against the bone portion with a fastener;
[0130] FIG. 22A is a perspective view of another embodiment of an
interbody spacer showing an anterior, proximal, and superior
surface thereof;
[0131] FIG. 22B is a perspective view of an embodiment of an
interbody spacer illustrating a posterior, proximal, and superior
surface thereof;
[0132] FIG. 22C is a side view of a spacer embodiment;
[0133] FIG. 22D is a top view of one embodiment of a spacer;
[0134] FIG. 23A is a perspective view of one embodiment of a
stabilizer;
[0135] FIG. 23B is a perspective view of a stabilizer with its base
nose just beginning to enter into a channel of a spacer, with a
portion of the spacer resected for reviewing purposes;
[0136] FIG. 23C is a side view of a stabilizer as it begins to
insert into the channel of a spacer, with a portion of the spacer
resected for viewing purposes;
[0137] FIG. 23D is a side view of a stabilizer with self retaining
clips deflecting into deflection pockets as the stabilizer is
further translated into the spacer, with a portion of the spacer
resected for viewing purposes;
[0138] FIG. 23E is a side view of a stabilizer fully docked within
a spacer and self retaining clips fully seated within stop pocket,
with a portion of the spacer resected for viewing purposes;
[0139] FIG. 24A is a front view of a spacer-stabilizer assembly
installed within the intervertebral space, with the superior and
inferior vertebral bodies partially resected for viewing of the
deployed stabilizers as they would reside in the bone;
[0140] FIG. 24B is a perspective view of a spreader used to deploy
the tabs of the stabilizer;
[0141] FIG. 24C is a perspective view of a spreader driver
tool;
[0142] FIG. 24D is a close-up perspective view of a drive head of
the spreader driver tool;
[0143] FIG. 25A is a perspective view of a spacer with a stabilizer
docked therein, with a spreader partially seated within the
stabilizer;
[0144] FIG. 25B is a perspective view of a spacer with a stabilizer
docked therein, a spreader partially seated within the stabilizer
wherein the nose of the spreader begins contact with the internal
surface of the stabilizer tabs;
[0145] FIG. 26A is a perspective view of a spacer/cage inserter
tool;
[0146] FIG. 26B is a perspective view of a locking shaft utilized
inside the spacer/cage inserter tool for holding the spacer tight
to the inserter tool;
[0147] FIG. 26C is a perspective view of an accessory guide holder
illustrating a locking mechanism;
[0148] FIG. 26D is a perspective view of an accessory guide holder
illustrating an opposing view of a locking mechanism;
[0149] FIG. 27A is a perspective view of a drill guide;
[0150] FIG. 27B is a perspective view of the proximal portion of a
drill guide illustrating a positioner for docking with the spacer
inserter tool;
[0151] FIG. 27C is a perspective view of the distal portion of a
drill guide illustrating the drill guide tip;
[0152] FIG. 27D is a perspective view of a drill configured for use
with a drill guide and a partial view of a drill illustrating a
collection recess;
[0153] FIG. 27E is a perspective view of a drill guide body and
drill docked with a spacer inserter tool;
[0154] FIG. 27F is a perspective view of the distal portion of a
drill guide-spacer inserter assembly illustrating the interface
between a tool and spacer;
[0155] FIG. 27G is a perspective view of a drill-guide spacer
inserter assembly and drill secured to the spacer;
[0156] FIG. 27H is a perspective view of a drill guide docked to a
spacer with drill fully inserted in the drill guide, with the
spacer inserter tool hidden;
[0157] FIG. 28A is a perspective view of a stabilizer inserter;
and
[0158] FIG. 28B is a close-up perspective view of the stabilizer
inserter illustrated in FIG. 28A.
[0159] FIG. 29 is a perspective view of a preferred embodiment of
an assembly of a spacer, an alternative spacer inserter, and
locking shaft.
[0160] FIG. 30 is a close-up perspective view of the end of a
spacer inserter.
[0161] FIG. 31 is a partial perspective view of the proximal end of
a spacer inserter body.
[0162] FIG. 32 is perspective view of the proximal end of a spacer
inserter body.
[0163] FIG. 33 is a proximal end view of the inserter illustrated
in FIG. 29 with attached spacer. The view illustrates alignment of
the channels from instrument to implant (longitudinal guide of
inserter to anchor portion of spacer).
[0164] FIG. 34 is a distal end view of opposing graft blocks.
[0165] FIG. 35 is an end perspective view of opposing graft
blocks.
[0166] FIG. 36 is a perspective view of a preferred drill
guide.
[0167] FIG. 37A is a close-up proximal perspective view of the
drill guide of FIG. 36.
[0168] FIG. 37B is a close-up distal perspective view of the drill
guide of FIG. 36.
[0169] FIG. 38A is a side perspective view of a trial spacer.
[0170] FIG. 38B is a side perspective view of an extension
handle.
[0171] FIG. 39 is a proximal perspective view of a graft block
preparing for insertion into a longitudinal guide of a spacer
inserter.
[0172] FIG. 40 is proximal perspective view of the graft block
sliding down the inserter.
[0173] FIG. 41 is a partial perspective view of the containing face
covering the graft opening.
[0174] FIG. 42 is a partial perspective view of the spacer graft
opening covered on an inferior side and ready to be packed with
bone graft.
[0175] FIG. 43 is a partial proximal perspective view of a second
graft block being loaded into the inserter.
[0176] FIG. 44 is a partial perspective view of a spacer secured to
the spacer inserter with graft blocks fully enclosing the graft
opening of the spacer.
[0177] FIG. 45 is a partial perspective view of the stop faces of
each graft block abutting the vertebral bodies just as the spacer
begins entry into the intervertebral space.
[0178] FIG. 46 is a partial perspective view of the graft blocks
retracting as the spacer enters the intervertebral space.
[0179] FIG. 47 is a partial perspective view of the spacer fully
inserted into the intervertebral space.
[0180] FIG. 48 is a perspective view of the graft blocks being
removed from the surgical site.
[0181] FIG. 49 is a partial perspective view of the drill guide
inserted into an inserter channel.
[0182] FIG. 50 is a partial perspective view of the drill guide
fully advanced on the inserter and prepared for entry of the
drill.
[0183] FIG. 51 is a partial close-up view illustrating the drill
guide stop fully advanced.
[0184] FIG. 52 is a partial perspective view illustrating the nose
of a stabilizer advanced into a channel on the longitudinal guide
(stabilizer inserter not shown).
[0185] FIG. 53 is a partial perspective view of a stabilizer fully
advanced into the predrilled hole in the vertebral body.
[0186] FIG. 54 is a partial perspective view of the drill guide
reintroduced in preparation for the stabilizer spreader.
[0187] FIG. 55 is a partial perspective view of the spreader
inserted in the drill guide and advanced into the stabilizer.
DETAILED DESCRIPTION OF SELECTED EMBODIMENTS OF THE INVENTION
[0188] Embodiments of the invention will now be described with
reference to the Figures. The terminology used in the description
presented herein is not intended to be interpreted in any limited
or restrictive way, simply because it is being utilized in
conjunction with detailed description of certain specific
embodiments of the invention. Furthermore, embodiments of the
invention may include several novel features, no single one of
which is solely responsible for its desirable attributes or which
is essential to practicing the invention described herein.
[0189] FIG. 1 illustrates schematically one embodiment of an
interbody spacer 100. The spacer 100 can be used between any
adjacent bone portions, such as members at a joint, in a void
between such joint portions as might be developed by a fracture,
through a procedure that removes bone as with a tumor, etc. While
the invention is contemplated for use with virtually any adjacent
bone portions between which a spacer is required, the initial
disclosure herein will be directed towards spinal procedures
wherein the spacer 100 is placed between adjacent vertebrae/joint
members that make up a subset of the more generically referenced
bone portions.
[0190] Embodiments of the invention can be incorporated in any
number of interbody or vertebral body replacement devices,
including for example, the devices shown in FIGS. 8A-8M. All of the
interbody spacer devices shown in FIGS. 8A-8M are commercially
available from Alphatec Spine.TM., Inc. (See website at:
http://www.alphatecspine.com/products/interbody.asp). FIGS. 8A and
8B depict top perspective views of two configurations PA1, PA2 of
the "Novel Cervical Interbody System" for use in an anterior
cervical fusion procedure. FIGS. 8C-8F show top perspective views
of four different configurations PA3, PA4, PA5, PA6 of the "Novel
CP Vertebral Body Replacement System" for use in the thoracolumar
spine (T1-L5). FIGS. 8G and 8H illustrate two "Novel VC Spinal
Spacers" PA7, PA8 for use in Anterior Lumbar Interbody Fusion
(ALIF), made of PEEK or titanium. FIGS. 8I and 8J depict two "Novel
SD" interbody spacer devices PA9, PA10 made of PEEK or titanium,
for use in a Posterior Lumbar Interbody Fusion (PLIF). FIGS. 8K and
8L show two "Novel LCC Spacer" devices PA11, PA12 made of PEEK and
titanium, for use in a Posterior Lumbar Interbody Fusion (PLIF).
FIG. 8M illustrates a "Novel TL Spacer" device PA13 for use in a
Transforaminal Lumbar Interbody Fusion (TLIF).
[0191] The spacer 100 is used in spinal fusion surgeries including
ALIF, PLIF and TLIF procedures, wherein two or more vertebrae are
joined or fused together for the treatment of spinal disorders such
as spondylolisthesis, scoliosis, severe disc degeneration, or
spinal fractures. The embodiments below are described primarily in
the context of an ALIF procedure, though other spinal implants and
procedures are also contemplated.
[0192] The spacer 100, shown schematically in FIG. 1 and
contemplated to have the shapes of any of the conventional spacers
PA1-PA13, described above, or any other suitable shape, includes
first and second opposite surfaces 120 and 130 respectively
configured to engage superiorly and inferiorly the end plates of
adjacent vertebrae. As shown for the spacers in FIGS. 8A-8M, these
corresponding surfaces PA20 and PA30 may have ridges, bumps or
other protrusions PA35 to enhance engagement with the vertebral
endplates. As also shown in FIGS. 8A-8M, these surfaces PA20 may
define openings PA40 (not shown in FIG. 1) to allow for fusion
through the openings.
[0193] In the embodiment shown in FIG. 1, the first and second
surfaces 120 and 130 are substantially flat and parallel. However,
in other embodiments, the first and second surfaces can be angled
relative to each other and may be non-flat, so as to better support
adjacent vertebral bodies in a more natural spinal alignment
configuration. For example, the first and second opposite surfaces,
PA20 and PA30 of the interbody spacer shown in FIG. 8A, are
slightly angled toward each other in the direction of the posterior
surface PA42. Additionally, the first and second opposite surfaces,
PA20 and PA30 of the interbody spacers shown in FIGS. 8I and 8J,
are tapered toward each other toward the ends PA44 of the interbody
spacers.
[0194] The spacer 100 has a proximal face 140 and a distal face
150, the proximal face 140 corresponding to the end that engages a
delivery tool, such as with grooves or indentations PA46 or a
threaded opening PA48 as shown in FIGS. 8A-8M. For an ALIF
procedure, the proximal face 140 corresponds to the anterior face
of the spacer (such as the convex surface PA50 in FIGS. 8G and 8H),
and the distal face 150 corresponds to the posterior face of the
spacer (such as the flat surface PA52 in FIG. 8H).
[0195] As illustrated in FIG. 1, the spacer 100 has three channels
155 for receiving suitable complementary stabilizers (discussed in
further detail below), although it is to be understood that in
other embodiments the spacer can have only one channel and in yet
other embodiments, the space can have any number of channels.
[0196] The channels 155 interface with the first and second
surfaces 120 and 130 of the spacer 100, as well as with at least
the proximal surface 140 of the spacer 100. The channels 155 shown
in FIG. 1 are shown extending through the body of the spacer 100,
and interfacing with the distal surface 150 of the spacer 100.
However, in other embodiments, the channels do not extend all the
way through the spacer body to interface with the distal surface of
the spacer and in other embodiments the channels 155 can interface
with side surfaces 160 and 170. The channels 155 are preferably
pre-cut into the spacer body 100 before insertion into the
vertebral space during surgery. Where the spacer 100 has openings
in the surfaces 120 and 130, the channels 155 may extend through
solid portions of the spacer between the openings (such as through
the intermediate bar PA54 shown in FIG. 8G, or may be interrupted
by the openings PA40 so that the channels are provided on opposite
sides of the openings PA40).
[0197] The interbody spacer 100 can be made of a rigid and durable
biocompatible material such as titanium, titanium alloy, stainless
steel iron steel and compositions thereof. Additionally, or
alternatively, non-metal biocompatible materials such as cadaveric
bone, polymers, elastomers, resins, ceramics and composites thereof
can be employed. In a preferred embodiment, the interbody spacer is
made of Polyetheretherketone (PEEK).
[0198] FIGS. 2 and 3 illustrate one embodiment of a stabilizer 200
suitable for use with the spacer 100 of FIG. 1, where FIG. 3 is an
end view of the stabilizer of FIG. 2. The stabilizer 200 is
configured to be partially received within the channels 155 of the
spacer 100, with a portion extending out of the channel away from
the surface 120 or 130 into the adjacent vertebral body. The
stabilizer 200 is preferably thin enough to slice through bone, yet
strong enough to hold onto the bone and stabilize the spacer 100
after insertion.
[0199] The stabilizer 200 as illustrated has three plates/walls
240, 250 and 260 attached together and configured in a "Z" shape as
seen in FIG. 2. The stabilizer 200 can also be formed from a single
plate which is bent to form the "Z" shape seen in FIG. 2. The
stabilizer 200 is preferably made of titanium. However, it can also
be made of any suitable material including, but not limited to:
polycarbonate, urethane and PEEK. The stabilizer 200 preferably has
sharp edges 264 and 266 which are thin and strong enough to slice
through vertebral bone when a sufficient force is applied to the
anterior surface 270 of the stabilizer 200. The stabilizer
translates along a line (L in FIG. 2) under the applied force to be
pressed into the bone portion to which it is aligned for this and
other embodiments herein. The sharp edges 264, 266 may be at both
ends so that the stabilizer can be inserted with either end thereof
in a leading direction. The stabilizer 200 can also have
self-retaining clips 272 attached to it to help keep the stabilizer
attached to the spacer after insertion, as will be discussed in
further detail below.
[0200] FIG. 4 shows the spacer 100 operably implanted within a
spine 402 from the anterior side of the spine. The spine 402
includes bone portions/vertebrae 410, 420. The spine 402 also
includes a diseased/damaged disk 430 that has been partially
removed and replaced with the spacer 100.
[0201] During operation, the diseased/damaged disk 430 is partially
or completely removed and preferably replaced with the spacer 100
with the proximal surface 140 of said spacer 100 facing anteriorly.
Stabilizers 200 are then lined up with the channels 155 of the
spacer 100 and driven by translational movement into the vertebral
bodies 410, 420 by applying sufficient force to the stabilizers
200. The stabilizers 200 are simultaneously driven into the
vertebral bones 410, 420 and received into their respective
channels 155. However, it is to be understood that in some
embodiments, stabilizers 200 can be inserted into the vertebral
bone before spacer 100 is inserted.
[0202] As mentioned previously, the stabilizer 200 can further
include self-retaining clips 272 (see FIG. 2) to fixedly attach the
stabilizers 200 to the spacer 100 after insertion. The
selfretaining clips 272 of FIG. 2 are attached to the stabilizer
200 and curve outward. The selfretaining clips 272 are made of a
resilient material which allows them to retract during insertion.
Once the stabilizers are inserted, the self-retaining clips 272
expand and push against the inner wall of the channel 155,
resisting withdrawal. The inner walls of the channels 155 can be
made rough or with notches to further aid the self-retaining clips
272 in resisting withdrawal.
[0203] It will be appreciated that the stabilizer 200 can have a
variety of shapes and that the spacer 100 can be configured with
complementary channels shaped to receive the stabilizer 200.
[0204] FIGS. 5A and 5B illustrate an alternative embodiment of a
stabilizer 500 suitable for use with a spacer (not shown), having
channels shaped to receive the stabilizer 500. FIG. 5A is a top
perspective view of the stabilizer and FIG. 5B is an end view of
the stabilizer of FIG. 5A. As illustrated, the stabilizer 500 has a
substantially sinusoidal configuration. While not illustrated, the
spacer for use with the stabilizer 500 has a complementary channel
having a substantially sinusoidal shape configured to receive the
stabilizer 500. The complementary channel can be oriented
perpendicular to the upper and lower surfaces of the spacer, or in
any other orientation which would allow the stabilizer 500 to
fixedly attach the spacer to an adjacent vertebral body.
[0205] FIGS. 6A-6J show various end views of alternative
embodiments of differently shaped stabilizers, by way of example
and not limitation. One of skill in the art will appreciate that
any number of differently shaped stabilizers can also be used,
though not identically disclosed herein, without departing from the
spirit of the invention. Many of these embodiments include a length
configured to span between the spacer and the vertebral body, but
also a transverse component (not shown in FIGS. 6A-6J) in both the
spacer-engaging portion and the vertebral-body engaging portion
configured to prevent separation between the spacer and vertebral
body.
[0206] FIG. 6A illustrates an end view of a substantially "S"
shaped stabilizer 601 suitable for use with a spacer (not shown),
having channels shaped to receive the stabilizer 601. While not
illustrated, the spacer for use with the stabilizer 601 has a
complementary channel with a substantially "S" shape, configured to
receive the stabilizer 601. The complementary channel can be
oriented perpendicular to the upper and lower surfaces of the
spacer, or in any other orientation which would allow the
stabilizer 601 to fixedly attach the spacer to an adjacent
vertebral body.
[0207] FIG. 6B illustrates an end view of a substantially double
"Z" shaped stabilizer 602 configuration suitable for use with a
spacer (not shown), having channels shaped to receive the
stabilizer 602. While not illustrated, the spacer for use with the
stabilizer 601 has a complementary channel having a substantially
double "Z" shape, configured to receive the stabilizer 602. The
complementary channel can be oriented perpendicular to the upper
and lower surfaces of the spacer, or in any other orientation which
would allow the stabilizer 602 to fixedly attach the spacer to an
adjacent vertebral body.
[0208] FIGS. 6C-6J similarly illustrate end views of uniquely
shaped stabilizers 603-610 configured for use with suitable spacers
(not shown) having complementary channels shaped to receive each
uniquely shaped stabilizer. The complementary channels can be
oriented perpendicular to the upper and lower surfaces of the
spacer, or in any other orientation which would allow the
stabilizers to fixedly attach the spacers to an adjacent vertebral
body.
[0209] FIG. 7 depicts a front end view of yet another embodiment of
an interbody spacer 700. The spacer 700 has channels 755 configured
to receive at least one stabilizer, such as the stabilizer 605 (see
FIG. 6E). The spacer 700 has first and second surfaces, 760 and 770
respectively, configured to engage adjacent vertebral end plates.
In this embodiment, the first and second surfaces 760 and 770 are
substantially parallel. However, in other embodiments, the first
and second surfaces can be angled relative to each other, so as to
better support adjacent vertebral bodies in a more natural spinal
alignment configuration. The spacer 700 of the present embodiment
has two channels 755 for receiving stabilizers such as the
stabilizer 605, although it is to be understood that in other
embodiments, the spacer 700 can have only one channel or more than
two channels.
[0210] The interbody spacer 700 can be provided with self-retaining
clips 780 to help keep the stabilizers attached to the spacer 700
after insertion. The self-retaining clips 780 can be attached to
the proximal surface 785 of spacer 700 and partially extend in
front of the channels 755. Preferably, the self-retaining clips 780
have a first and a second position. In the first position, the clip
780 is retracted during insertion of the stabilizer. After the
stabilizer is inserted, the clip 780 extends, assuming a second
position. The self-retaining clips 780 can be made of a resilient
material which allows them to bend inward during insertion of a
stabilizer. Once the stabilizer is inserted into the spacer, the
self-retaining clips 780 can "pop out" towards their original
positions to impede withdrawal of the stabilizers.
[0211] FIG. 9 illustrates schematically another embodiment of an
interbody spacer 900, similar to the spacers seen in FIGS. 8G and
8H depicting various "Novel VC Spinal Spacers" for use in Anterior
Lumbar Interbody Fusion (ALIF), which are commercially available
from Alphatec Spine.TM., Inc. (See website at:
http://www.alphatecspine.com/products/interbody.asp).
[0212] In preferred embodiments, the spacer 900 is used in spinal
fusion surgeries, including ALIF procedures, though other implants
and procedures are also contemplated.
[0213] The spacer 900, shown schematically in FIG. 9, includes
first and second opposite surfaces, 920 and 930 respectively
configured to engage superiorly and inferiorly the end plates of
adjacent vertebrae. These surfaces 920 and 930 may have ridges,
bumps or other protrusions to enhance engagement with the vertebral
endplates as discussed above, and shown in FIGS. 8A-8M. As shown in
FIG. 9, the first and second opposite surfaces, 920 and 930 may
define openings 932 to allow for fusion through the openings. In
the embodiment shown in FIG. 9, the first and second surfaces 920
and 930 are substantially parallel. However, in other embodiments,
the first and second surfaces can be angled relative to each other,
so as to better support adjacent vertebral bodies in a more natural
spinal alignment configuration, as discussed previously.
[0214] The spacer 900 has a proximal face 934 and a distal face
936, the proximal face 934 corresponding to the end that engages a
delivery tool, such as with grooves, indentations or a threaded
opening 938, similar to that discussed above with reference to
FIGS. 8A-8M. For an ALIF procedure, the proximal face 934
corresponds to the anterior face of the spacer and the distal face
936 corresponds to the posterior face of the spacer.
[0215] As illustrated in FIG. 9, the spacer 900 has two channels
955 for receiving suitable stabilizers (discussed in further detail
below), although it is to be understood that in other embodiments
the spacer can have only one channel and in yet other embodiments,
the spacer can have any number of channels.
[0216] The channels 955 interface with the first and second
surfaces 920 and 930 of the spacer 900, as well as with at least
the proximal surface 934 of the spacer 900. The channels 955 shown
in FIG. 9 extend through the body of the spacer 900, and interface
with the distal surface 936 of the spacer 900. However, in other
embodiments, the channels do not extend all the way through the
spacer body to interface with the distal surface of the spacer and
in other embodiments the channels 950 can interface with side
surfaces 960 and 970. The channels 955 are preferably precut into
the spacer 900 before insertion into the vertebral space during
surgery. Where the spacer 900 has openings 932 in the surfaces 920
and 930, the channels 955 may extend through solid portions of the
spacer 900 between the openings 940 (such as through the
intermediate bar 972 shown in FIG. 9), or they may be interrupted
by the openings 932 so that the channels 955 are provided on
opposite sides of the openings 932.
[0217] FIGS. 10 and 11 illustrate one embodiment of a stabilizer
1000 suitable for use with the spacer 900 of FIG. 9, where FIG. 10
is an end view of the stabilizer 1000 and FIG. 11 is a perspective
view of the stabilizer 1000. The stabilizer 1000 is configured to
be partially received within the channels 955 of the spacer 900,
with a portion extending out of the channel 955 away from the
surface 920 or 930 into the adjacent vertebral body. The stabilizer
1000 is preferably thin enough to slice through bone, yet strong
enough to hold onto the bone and stabilize the spacer 900 after
insertion. The stabilizer 1000, as illustrated, has two
plates/walls 1050 and 1060 and a wall/retaining member 1070
attached together and configured in a "T" shape as seen in FIG. 10.
The stabilizer 1000 is preferably made of metal but it can also be
made of any suitable material including, but not limited to:
Ti-6Al-4V, ELI, ASTM F 136, commercially pure titanium (for
example, Ti-CP2, ASTM F 67, CPTi, etc.). The plates 1050 and 1060
of stabilizer 1000 preferably have sharp edges 1072 and 1074 which
are thin and strong enough to slice through vertebral bone when a
sufficient force is applied to the anterior surface 1076 of
stabilizer 1000. Stabilizer 1000 can also have self-retaining clips
(not shown) attached to it to help keep the stabilizer 1000
attached to the spacer 900 after insertion, as discussed
previously.
[0218] FIG. 12 is an end view of the spacer 900 of FIG. 9 operably
implanted within a spine 1201 from the anterior side of the spine.
The spacer 900 is inserted between two bone portions/vertebrae 1210
and 1220 and two stabilizers 1000, according to FIGS. 10 and 11,
are inserted into the channels 955 of the spacer 900 and into the
adjacent vertebral bodies 1210 and 1220.
[0219] During operation, the diseased/damaged disk (not shown) is
partially or completely removed and preferably replaced with a
spacer 900 with the proximal surface 934 of said spacer 900 facing
anteriorly. Stabilizers 1000 are then lined up with the channels
955 of the spacer 900 and driven translationally into vertebral
bodies 1210 and 1220 by applying sufficient force to the
stabilizers 1000. The stabilizers 1000 are simultaneously driven
into the vertebral bones 1210 and 1220 and received into their
respective channels 955. However, it is to be understood that in
some embodiments, stabilizers 1000 can be inserted into the
vertebral bones 1210 and 1220 before spacer 900 is inserted. It is
further conceivable, with this and other embodiments, that the
stabilizers could be pre-joined to their respective spacer before
the stabilizer is translated into the bone portions.
[0220] It should be understood that all of the particular
structures described in each embodiment may be used in any other
embodiment. That is, the invention contemplates that the different
features in the embodiments disclosed herein may be
interchanged.
[0221] As noted previously, it is contemplated that the invention
can be practiced as part of any medical procedure involving the
placement of a spacer between adjacent bone portions. This generic
concept is shown schematically in FIG. 13, wherein a spacer 1300,
representing all spacer configurations disclosed herein, as well as
others, is operatively joined to at least a first bone portion
1302. It is conceivable that the spacer 1300 would be joined to
only the first bone portion 1302. However, more commonly, the
invention would be practiced by using the spacer 1300 between the
first bone portion 1302 and a second bone portion 1304, which is
shown to be optional by the depiction of the latter schematically
in FIG. 13 in dotted lines. The stabilizer 1306, as shown in FIG.
13, is intended to represent all stabilizer constructions disclosed
herein, as well as others. The stabilizer 1306 operatively
interacts between the spacer 1300 and either of the bone portions
1302, 1304.
[0222] With the system as shown in FIG. 13, the spacer 1300 is
configured to be placed between the first and second bone portions
1302, 1304. The stabilizer 1306 is configured to be joined: a) to
each of the first bone portion 1302 and spacer 1300; and b) to at
least one of the first bone portion 1302 and spacer 1300 by being
translated relative to the at least one of the first bone portion
1302 and spacer 1300 along a first line.
[0223] As noted previously, the stabilizer 1306 preferably extends
into its associated bone portion 1302, 1304 over a majority of the
dimension of that bone portion 1302, 1304 along a corresponding
first translation line L, as seen in FIG. 2 for the stabilizer
200.
[0224] As seen in FIGS. 2 and 3, the stabilizer 200 has the
aforementioned plates/walls 240, 250, 260, with a first and second
of the walls 250, 260 having facing surfaces S1, S2, respectively.
With the stabilizer operatively positioned, as seen in FIG. 4, a
part P1 of the vertebra 420 and a part P2 of the spacer 100 are
captive between the facing surfaces S1, S2 to stabilize the spacer
and bone portion/member 420.
[0225] Because each of the plates/walls 240, 250, 260 has a
substantial width dimension transversely to the line L, the
connection is stabilized in all critical dimensions. Preferably,
the plates/walls 240, 260 extend into the spacer 100 along a
majority of the dimension of the spacer 100 along the line L. More
preferably, the spacer walls 240, 250, 260 extend along
substantially the entire dimension of the spacer 100 along the line
L.
[0226] Each of the stabilizer configurations defined herein has
surfaces that produce the above captive arrangement. By reason of
the depicted configurations, these stabilizers also produce
multidimensional reinforcement between the fused components.
[0227] As seen in FIG. 4, the spacer surface 120 abuts to an
adjacent surface AS1 on the vertebra 410, with the opposite spacer
surface 130 abutting the adjacent surface AS2 on the vertebra 420.
It is contemplated that the stabilizers 200 extend through at least
one of the surfaces 120, AS1 and 130, AS2 at locations where the
surfaces abut. More preferably, each stabilizer extends
continuously through each of the adjacent faces 120, AS1 and 130,
AS2.
[0228] It is conceivable that a spacer could be devised having a
U-shaped configuration, with spaced legs parallel to each other and
the line L, such that the spacer does not penetrate any of the
surfaces 120, 130, AS1, AS2. This spacer would be inserted
similarly in a translational path.
[0229] As seen in FIG. 4, the surfaces 120, 130, AS1, AS2 are shown
to be generally flat and parallel to each other. The translation
line for the stabilizers 200 during assembly is substantially
parallel to each of the surfaces 120, 130, AS1, AS2.
[0230] As also seen in FIG. 4, the inventive stabilizer 200 is
constructed so that it extends only partially through the dimension
of the spacer 100 between the surfaces 120, 130.
[0231] As further seen in FIG. 4, each of the components 410, 420,
100 has a peripheral surface, PS1, PS2, PS3. The stabilizers 200
can be constructed so that the stabilizers do not project from any
of the exposed peripheral surfaces PS1, PS2, PS3. While preferred,
this is not a requirement.
[0232] Additional variations of the inventive structure are shown
in FIGS. 14-21.
[0233] In FIG. 14, a fenestrated form of stabilizer 1400 is
depicted with a configuration corresponding to the stabilizer 610
in FIG. 6J. The stabilizer 1400 has flat walls 1402, 1404 which
combine to produce a "T" shape. A cylindrical wall 1406 is provided
at the bottom of the "T".
[0234] The wall 1402, that is embedded in the bone, has discrete
openings 1408 into which bone can grow to thereby further secure
the connection between the stabilizer 1400 and bone.
[0235] In FIG. 15, a stabilizer 1500 is shown for use in
conjunction with a spacer 1502 and bone portion 1504 to cause
facing surfaces 1506, 1508 on the spacer 1502 and bone portion 1504
to be urged towards each other with a progressive camming action as
the stabilizer 1500 is inserted.
[0236] The stabilizer 1500 has flat walls 1510, 1512 that produce a
"T" shape, at the bottom of which a cylindrical wall 1514 is
provided. The wall 1510 resides within a reference plane RP. The
wall 1514 has a central axis 1516 that is non-parallel to the
reference plane RP. More specifically, the axis 1516 is oriented so
that the space between the reference plane RP and axis 1516
increases between the trailing end 1518 and leading end 1520.
[0237] The spacer 1502 has a channel 1523 to accept the wall 1514
and a part of the wall 1512. The axis 1524 of the channel portion
that accepts the cylindrical wall 1514 is substantially parallel to
the spacer surface 1506. As a result, as the leading end 1520 is
translated into the channel 1523 and the wall 1510 cuts into the
bone portion 1504, the movement of the cylindrical wall 1514 into
the channel 1523 produces a camming action that progressively urges
the surfaces 1506, 1508 against each other.
[0238] In FIG. 16, a stabilizer 1600 is shown in relationship to a
spacer 1602 and bone portion 1604, wherein a similar camming action
is produced by essentially reversing the construction shown in FIG.
15. That is, the axis 1606 on the spacer 1602, that corresponds to
the axis 1524, is inclined relative to the spacer surface 1608,
whereas the axis 1610 for the cylindrical wall 1612 is
substantially parallel to a reference plane RP1 containing the flat
wall 1616.
[0239] Using the concepts disclosed in FIGS. 15 and 16, the
components can be configured to produce the desired compressive
force between a spacer and bone portion, as well as potentially
producing such a force at both sides of the bone portion.
[0240] While the walls 1514, 1612 are shown with a cylindrical
shape, it is contemplated that the shape may be non-circular in
cross-section so as to be keyed within the cooperating channel to
further stabilize the connected spacer and bone portion.
[0241] The invention also contemplates that locking assemblies
might be incorporated into the stabilizers and spacers to avoid
inadvertent backing out or extension of the particular stabilizer
at a fusion location. In FIG. 17, one form of locking assembly is
shown at 1700. A stabilizer 1702 has the same general construction
as the stabilizer 1600 in FIG. 16, with the exception that there is
an enlargement 1704 on the trailing end thereof. A cooperating
spacer 1706 has a complementary channel 1708 including an enlarged
receptacle 1710 that is complementary to the enlargement 1704. The
enlargement 1704 and receptacle 1710 define cooperating connecting
parts on the locking assembly 1700. With the stabilizer 1702
translated along the line L to a fully inserted position, the
enlargement 1704 snap fits into the receptacle 1710 to produce a
detenttype action.
[0242] In the depicted embodiment, the enlargement 1704 is
countersunk so as to not project from the spacer 1706. However, the
parts could be configured so that there is a flush relationship or
a projection of the enlargement 1704 from the spacer 1706.
[0243] With this arrangement, the locking assembly 1700 maintains
the stabilizer 1702 in its operative position shown in FIG. 17.
[0244] Another type of locking assembly is shown in two different
forms in FIGS. 18-20. The locking assembly in FIGS. 19 and 20
consists of a reconfigurable body 1800 on a stabilizer 1802. The
stabilizer 1802 is directed into a channel 1806 on a spacer 1808.
The channel 1806 has a flared region 1810 inset from a wall portion
1812. The flared region 1810 defines an annular shoulder 1814 set
inwardly from a surface 1815 on the spacer 1808.
[0245] With the stabilizer 1802 translated into the channel 1806, a
bifurcated end 1820 of a cylindrical wall 1822 resides at the
flared region 1810. The bifurcation at the end 1820 produces
diametrically opposite tabs 1830, 1832 between which a threaded
spreader element 1840 can be directed. The spreader element 1840
has an outer surface 1842 with a portion having a progressively
increasing diameter. By threading the spreader element 1840 into
the wall 1822, the tabs 1830, 1832 are reconfigured by bending
radially outwardly to seat behind the annular shoulder 1814,
whereupon the stabilizer 1802 is blocked from being withdrawn. The
spreader element 1840 thus changes the locking assembly from the
assembly state, as shown in solid lines in FIGS. 19 and 20, to a
locked state as shown in dotted lines in FIG. 20. The tabs 1830,
1832 and flared region 1810 make up cooperating connecting parts on
the locking assembly.
[0246] In FIG. 18, the locking assembly consists of corresponding
tabs 1830', 1832', on a stabilizer 1802', that cooperate with a
complementarily-shaped region 1810' of a channel 1806'. The tabs
1830', 1832' may spring oppositely into the region 1810' without
requiring insertion of a separate spreader element.
[0247] As an alternative form of locking assembly, as shown in FIG.
21, a stabilizer 1900 is provided with a locking tab 1902. The
locking tab 1902 has a bore 1904 therethrough and is bent on site
or pre-bent to be substantially orthogonal to the plane of a wall
1906 on the stabilizer 1900. With this arrangement, the locking tab
1902 overlies a part of the exposed bone portion 1910 whereby a
threaded fastener 1920 can be directed therethrough. The fastener
1920 is preferably a threaded component. A similar tab (not shown)
might be provided to be securable to the cooperating spacer 1930 in
like fashion.
[0248] Threads 1940 might be provided around the bore 1904. The
threads 1940 may be interrupted or placed at multiple points to
allow for a controlled cross-threading of the head 1942 of the
fastener 1920 as it is inserted. This allows the fastener 1920 to
be inserted at any optimal angle.
[0249] In other variations, stabilizers, such as the stabilizer
1400, may be treated by applying bone ingrowth coating, as on the
wall 1402. The coating may be in the form of beads, mesh, or
hydroxyappetide. This promotes rapid ingrowth into the openings
1408. This same concept may be used on all other stabilizers
described herein.
[0250] FIGS. 22A-22D show a further variation of a spacer presented
earlier. Like the spacer 900 illustrated in FIG. 9, the spacer/cage
2200 has a body 2290 with side surfaces 2260, 2270, channels 2255,
2265, proximal and distal faces 2240, 2250, respectively, first and
second opposite surfaces 2210, 2220, an opening 2232 for graft or
other bone substitute material, and protrusions in the form of
teeth 2235.
[0251] FIGS. 23A-23E show a further modified form of stabilizer
2300. Like the stabilizers 1000, 1400 illustrated in FIGS. 10, 11,
& 14, the stabilizer 2300 has a wall/plate 2310, a web/wall
2320, and cylindrical wall/retaining member 2330 with a sharp
leading edge 2340 to cut bone against which it is advanced. The
stabilizer 2300 has self-retaining clips 2350 in the form of
barbs/tabs, generally of the type illustrated at 272 in FIG. 2.
[0252] The spacer body 2290 has a height "h" sized to fit within a
portion of the intervertebral disc space. The intervertebral space,
as defined by the shape/footprint of the vertebral body endplates,
is generally "D"-shaped and the implant spacer/cage 2200 preferably
has an outer profile shape to fill substantially the entire disc
space. Interbody implants may take streamlined profiles, as between
anterior and posterior sides, to provide less invasive entry into
the intervertebral space during surgery and to help accommodate to
the surgical approach. Regardless of their configuration, it is
desirable that the combined spacer and stabilizer have a
"zero-profile", meaning that no part of either component protrudes
from the space between adjacent bone portions. Exemplary differing
profiles are illustrated in FIGS. 8A-8M. For example, rectangular
or banana-shaped profiles may be used since they are thinner in a
width dimension, thereby requiring a smaller/less invasive path of
entry into the intervertebral disc space. In one preferred form
shown in FIG. 22A, an anterior wall portion 2275 of the implant,
that is part of a continuous profile wall 2280 and defines the
surface 2260, has a gentle convex arc similar to the anterior wall
of the vertebral body and a predetermined width between the
surfaces 2260 and 2270 to facilitate minimally invasive entry along
an axis/line generally parallel to the lengths of the channels 2255
and 2265.
[0253] The outer profile wall 2280 defines one or more openings
2232, 2295 for packing bone graft or other bone substitutes to
ultimately facilitate fusion between vertebral bodies. The opening
2232 is completely surrounded by the wall 2280 to hold the graft
material within the body 2290. The wall 2280 may have openings
partially or fully therethrough for packing graft. As seen in FIG.
22A, two graft apertures/openings 2295 are formed within the wall
2280 and can be utilized for adding additional graft or hydration
to the graft within the opening 2232.
[0254] The proximal face 2240 of the wall 2280 of the spacer/cage
2200 incorporates features for the attachment of one or more
auxiliary instruments utilized to install the spacer/cage 2200
within the intervertebral space. In this embodiment, instrument
attachment structure is in the form of two bores 2215a, 2215b with
at least one hole/bore 2215a threaded for attachment to a
complementarily-threaded insertion facilitating instrument,
identified schematically in FIG. 22A at 2205. The second hole 2215b
is also shown to be threaded, though this is not required, and
configured to engage a boss from the insertion instrument 2205 as a
means to counter torque and therein limit rotation between the
spacer/cage 2200 and insertion instrument 2205, to be described
later. The instrument attachment portion structure could also be in
other forms such as a boss, slot, hole, groove or other feature for
an auxiliary instrument to attach. If both holes/bores 2215a, 2215b
are threaded and usable individually to cooperate with the
instrument 2205, the unused hole/bore 2215a, 2215b is available as
a backup, as in the event one of the holes/bores becomes
stripped.
[0255] The distal face 2250 of the body 2290 has a nose portion
2400 as seen most clearly in FIG. 22C, configured to ease entry
into the intervertebral space by wedging between vertebral
endplates during insertion. This nose portion 2400 preferably has a
lead in angle taper at 2410, in combination with a radiused end
2420 defining a blunt arrow or bullet shape. As seen from the top
view in FIG. 22D, the side surfaces 2260, 2270 may also have a
taper or radius 2411 where they blend into the radiused end 2420 at
the distal face 2250. This is helpful to wedge soft tissue to the
sides of the nose portion 2400 during insertion.
[0256] The body 2290 also has a stabilizer attachment or anchor
portion 2245 for securement of the stabilizer 2300 to the
spacer/cage 2200. This anchor portion 2245 consists of one, and
preferably two, of the aforementioned channels 2255, 2265
illustrated and otherwise known as keel tracks in this embodiment.
The channels 2255, 2265 are at the site where the stabilizer 2300
attaches and is secured to the spacer body 2290. The channels 2255,
2265 are shown through the surfaces 2210 and 2220, but in some
embodiments may be on other surfaces, such as the surfaces 2260 and
2270. The channels 2255, 2265 are preferably configured wherein one
channel 2255 is adjacent one bone portion and the other channel
2265 is adjacent another between which the spacer/cage 2200
resides. The channels 2255, 2265 in this embodiment each is in the
form of a T-shaped slot preferably extending along a linear path,
although the path could be arced, when complemented by an arced
stabilizer, or otherwise shaped. The T-shaped slot shown is
configured to accept and contain a stabilizer, such as the
stabilizer 2300 with a body 2390. The stabilizer body 2390 has one
or more reconfigurable tabs/barbs 2350, and in this embodiment two
such tabs/barbs 2350 generally of the type 1830, 1832 shown in
FIGS. 19 and 20, and described in greater detail below.
[0257] At least one of the channels/keel tracks 2255, 2265 has a
stabilizer stop portion 2276, here illustrated as a termination of
the T-shaped channel 2255 which prevents the stabilizer 2300 from
advancing beyond the spacer body 2290 and the implant spacer/cage
2200 from advancing out of the intervertebral space once the
stabilizer 2300 is locked in a predetermined operative position
within the vertebral body. With the stabilizer body 2390 abutted to
the stop portion 2276, the stabilizer 2300 is consistently located
in its optimal operative relationship to the spacer/cage 2200. The
stabilizer anchor portion 2245 in this embodiment also has a
stabilizer lock portion illustrated in FIG. 22B as an undercut
region 2225 for receipt of the tabs/barbs 2350 on the stabilizer
2300.
[0258] In FIG. 22B, both of the opposite surfaces 2210, 2220 of the
body 2290, on the superior and inferior sides thereof, have
channels 2255, 2265 respectively formed therethrough with each
shown as a T-shaped slot. The body 2290 of the spacer/cage 2200 may
have one or more marker housings 2285 shown here in the form of
holes or other recess for the placement of tantalum markers M. The
markers M assist placement of the implant through imaging in the
predetermined intervertebral position.
[0259] As shown in FIGS. 22A and 22C, the first and second opposite
surfaces 2210, 2220 of the implant body 2290 ride directly against
bone. One or both surfaces 2210, 2220, as shown, may have one or
more of the teeth 2235 or other protrusions to assist securement of
the spacer/cage 2200 in its predetermined operative position
between the vertebral body bone portions BP1, BP2, as seen in FIG.
24A. The teeth 2235 preferably each has a peak 2236 which may be in
the form of a point, or broader surface such as a line, preferably
extending generally transverse to the entry line/axis. Each tooth
2235 has an entry face 2237 that may be sloped to assist moving the
implant body 2290 into the intervertebral space, and a trailing
face 2238 that is more steeply sloped to engage a bone portion to
prevent the implant body 2290 from backing out of the implant
space. The teeth 2235 are sized deep enough to dig into bone yet
shallow enough to avoid substantial loss of intervertebral space
following implant insertion once there is subsidence of the teeth
or other protrusions 2235.
[0260] The opposite surfaces 2210, 2220 are preferably optimized to
have enough area to adequately support and distribute the forces
between the vertebral body endplates while having adequate sized
openings 2232 for a strong fusion. In turn, the wall 2280 of the
body 2290 is thick enough such that it will not buckle under the
endplate forces, dependent on the material of construction. The
distance h, between the surfaces 2210, 2220, is generally equal to
the distance between vertebral body endplates when separated by a
healthy intervertebral disc. These surfaces could be generally
flat; however, they are preferably contoured to match the contour
of the facing vertebral endplate, which is typically slightly
convex. An example of the contour can be seen in FIG. 22C with the
height bulged slightly near the middle of the spacer/cage 2200.
Similarly, the opposite surface portions 2210, 2220 may be angled
in relation to each other to accommodate to the intervertebral
space. This space is commonly angled from anterior to posterior. As
an example, the embodiment in FIG. 22C is angled 6 degree, as
reflected by a slightly greater height on the anterior portion of
the implant and sloping to a slightly shorter height on the
posterior portion of the implant. This corresponds to the normal
angulation in the lumbar spine.
[0261] The stabilizer 2300 functions to: secure the body 2290
portion in a predetermined operative position relative the adjacent
bone portions; assist against back out and over travel of the
spacer/cage 2200 from this position; and help positively hold
surrounding bone close to the spacer 2200, thereby facilitating a
successful fusion. The wall/retaining member 2330 on the stabilizer
2300, in the preferred embodiment depicted, has a cylindrical
shape. The stabilizer 2300 has a reconfigurable body 2390,
generally of the type illustrated in FIGS. 19 and 20, but could
have a multitude of other configurations also described elsewhere.
The stabilizer 2300 may be integrated with the spacer/cage body
2290, but it is preferred that it be a separate component as shown
clearly in FIGS. 23A and 238. The stabilizer 2300 has a spacer
anchor 2370 that resides within the stabilizer anchoring portion
2245 on the spacer/cage 2200 with the spacer/cage 220 and
stabilizer 2300 operatively connected.
[0262] The base wall 2310 is flat and configured to be directed
into a complementarily-shaped portion of either of the channels
2255, 2265 on the body 2290. In this case, the base wall 2310 and
the flat web wall 2320 form a "T"-shaped portion to slide in and
reside in one of the Tshaped channels 2255, 2265. The cooperating
"T" shapes are such that the spacer anchor 2370 can be guided
consistently within the channels 2255, 2265 along the assembly
line/axis without excessive resistance but will be closely enough
matched to be stabilized in multiple dimensions relative to the
spacer/cage 2200 without appreciable wobble. The lower region of
the web wall 2320 is thickened where it engages the spacer/cage
2200. The exemplary channel 2255 is bounded by a surface 2266.
[0263] The complementary shapes of the channels 2255, 2265 and
spacer anchor 2370 may take many other forms besides a "T" shape.
For example, the base wall 2310 could have a triangular,
elliptical, or round profile. A leading nose 2311 on the base wall
2310 serves to lead the base wall 2310 into a channel 2255, 2265 of
the stabilizer anchor 2245. Similar to the spacer nose 2400, it is
preferred that the nose 2311 is tapered and radiused to ease entry.
As seen in FIG. 23C, the base wall nose 2311 extends slightly ahead
of a reconfigurable nose 2361 on the body 2390 such that the base
wall 2310 can begin to seat in one of the channels 2255, 2265
before the reconfigurable nose 2361 is situated to seat in the body
of the vertebrae, thereby easing insertion complications.
[0264] Any portion of the spacer anchor 2370, but preferably the
base wall 2310, includes a self-retaining portion. The base wall
2310 has a generally flat wall surface 2380 that is abuttable to
the spacer/cage surface 2266 to prevent pullout of the base wall
2310 from the channel 2255 in a direction transversely to the
channel length. A preferred configuration of the self-retaining
portion is shown in FIG. 23B in the form of the aforementioned
tab/barb 2350. One or more of the tabs/barbs 2350 may be used.
These tabs/barbs 2350, shown as two in number, are each configured
to engage the stabilizer lock portion, shown in the form of a like
number undercut regions 2225. The tabs/barbs 2350 are formed on the
stabilizer base wall 2310 and extend slightly below the base wall
2310. As the base wall 2310 is inserted into exemplary channel
2255, resilient arms 2351 on each tab/barb 2350 serially engage an
edge 2239 where a face 2241 bounding the channel 2255 meets the
proximal face 2240 and deflects up then re-seats itself under a
restoring force when it aligns over an undercut region 2225 on the
stabilizer interlock. This progression is illustrated in FIGS. 23B
through 23E.
[0265] A portion of the stabilizer body 2390 is cut away in the
illustrations for enhanced visualization. FIG. 23B illustrates the
leading base wall nose 2311 approaching one of the channels 2255
with the spacer 2200 and stabilizer in a pre-assembly relationship.
FIG. 23C illustrates the stabilizer 2300 partially seated into the
spacer/cage 2200 but before the tabs/barbs 2350 are engaged. FIG.
23D illustrates the stabilizer 2300 further translated into the
spacer/cage 2200. The underside surface of each self-retaining
tab/barb 235 abuts the bottom surface 2241 of the channel 2255 and
is guided therealong until the tabs/barbs 2350 align over their
respective undercut region 2225 whereupon a restoring force in the
deflector arms 2351 drives them into the undercut regions 2225. A
curved edge/blocking surface 2227 bounding each undercut region
2225 confronts the trailing edge/blocking surface of one of the
tabs/barbs 2350 to block the stabilizer 2300 from backing out. FIG.
23E illustrates the stabilizer 2300 fully translated into the
channel 2255 and the spacer 2200 and stabilizer in assembled
relationship. Stop 2275 prevents further translation of the
stabilizer 2300 moving in its assembly direction. The stabilizer
2300 is thus fully locked consistently in a preselected, optimal
operative position relative to the spacer/cage 2200.
[0266] The tabs/barbs 2350 may each have a sloped leading surface
2353 to assist deflection of the tabs/barbs 2350 upon entry and a
steeper surface 2354 on the trailing end of the tabs/barbs 2350 to
confront the edges 2227 bounding the undercut regions and prevent
backout. The transition between the leading surfaces 2353 and
trailing surfaces 2354 may be rounded to prevent hang-ups. The
spaces above the tabs/barbs 2350 are open to form relief pockets
2352 to allow for adequate deflection of the tabs/barbs 2350 when
inserting into the channel, as described previously. The barb arms
2351 are long enough to assure adequate deflection of the barbs
2350 while minimizing plastic deformation. The backout stop edges
2227 are each in the form of a steep wall located at the trailing
end of the undercut regions 2225, one of which is adjacent the
proximal face 2240 with the spacer 2200 and stabilizer 2300 in
operative relationship. The stop edges 2227 secure the stabilizer
2300 captively in conjunction with the stop portion 2276 and help
prevent the tabs/barbs 2350 from slipping out of the undercut
regions 2225 as might allow unintended release of the stabilizer
2300 from the spacer 2200.
[0267] With this arrangement, the stabilizer 2300 can be translated
in a first direction in a first path relative to the spacer/cage
2200 and thereby snap-fit consistently into the same operative
relationship therewith. The trailing surface 2354 and edges 2227
function as oppositely facing/blocking surfaces that confront each
other to prevent separation of the operatively joined stabilizer
2300 and spacer/cage 2200 with the spacer/cage 2200 and stabilizer
2300 in operative relationship.
[0268] One preferred interface between the flat base wall 2310 and
the channels 2255, 2265 is the depicted "T"-shaped configuration.
Although clearly other shaped channel interfaces can be used, such
as triangular, this "T"-shaped interface creates good stability
between the stabilizer 2300 and the spacer/cage 2200 and in turn
results in greater stability of the adjacent bone portions. The
"T"-shaped profile has beneficial strength to thickness ratio; that
is, the base wall 2310 is thin yet strong, therein maximizing the
material thickness of the spacer/cage 2200 available to secure the
stabilizer 2300 thereto. This permits narrower implants to be
created for use in patients having small stature or narrow disc
spaces. It is preferred that the interface gap between the surfaces
of the base wall 2310 and the walls bounding the channels 2255,
2265 is large enough to allow insertion of the stabilizer 2300 into
the track without struggle, yet small enough to minimize motion
between the two components, thereby adequately stabilizing the
surrounding bone.
[0269] Depending on where the implant is used in the skeleton, or
elsewhere as is also contemplated, the positioning of the
stabilizer 2300 on the spacer/cage 2200 may affect performance
and/or ease of insertion. Therefore the stabilizer 2300 may be
positioned midline or asymmetrically or at any number of angles
with respect to the body portion of the implant. For example, in
the illustrated and preferred embodiment of FIG. 22B, preferably
utilized for a lateral surgical approach, the stabilizer 2300 is
positioned to the posterior side of the implant as illustrated by
the position of the stabilizer anchor channels 2255, 2265. When
appropriately placed in the intervertebral space, this position
locks the stabilizer 2300 to the endplate of the vertebrae near the
center of axis of rotation between the vertebral bodies. This
placement is also particularly effective at resisting the vertebral
endplate from lifting away from the opposite surface portions 2210,
2220 of the implant body 2290. In this embodiment, the asymmetrical
positioning of the stabilizer 2300 also makes possible the use of a
single large opening 2232 for the bone graft instead of two smaller
ones. In most cases, the channels/keel tracks 2255, 2265 will be
generally collinear with the path of entry of the surgical
approach.
[0270] The web wall 2320 is typically in the form of a thin wall,
preferably about 1 mm or less, with a sharp leading edge 2340 to
slice through bone as the stabilizer is advanced in its assembly
direction and path, and has a profile narrower than the diameter of
the cylindrical wall 2330 so the cylindrical wall 2330 is captive
and cannot be pulled through the bone space created by the web wall
2320, thereby securing the bone tightly to the opposite surfaces
2210, 2220 of spacer/cage 2200. The web wall 2320 spans along a
majority of the length of the stabilizer 2300 between the
cylindrical wall 2330 and flat base wall 2310. It is preferred that
the cylindrical wall 2330, the web wall 2320, and the base wall
2310 all extend fully to the stabilizer's proximal face 2321, that
is substantially flat and resides in a plane generally orthogonal
to the length of the stabilizer 2300. The web wall 2320 is shown as
the shortest of the three walls. This wall length difference
facilitates insertion since the sharp edge 2340 will not encounter
the wall of the vertebral body until after the reconfigurable nose
2361 and the base wall nose 2311 are at least partially inserted
into the vertebral bone and channel 2255, 2265, respectively.
[0271] This web edge 2340 is sharpened to cut through bone during
insertion. This sharpened edge 2340 may be vertical or sloped
forward or back to facilitate the cutting action. In the preferred
embodiment, the web edge 2340 is straight, but may also be curved
or serrated. It is preferred that the web wall 2320 be continuous,
but it may include apertures for eventual bone ingrowth. However,
these should be limited so as to not substantially weaken the web
wall 2320. A continuous web will also ease future removal, if
necessary, since bone cannot grow through the web openings. The web
wall 2320 in FIG. 23A rises vertically from the flat wall track
2310; however, this web could rise at an angle or in a curved path
if so desired, as did those in earlier embodiments, such as that in
FIG. 2.
[0272] The cylindrical wall 2330 in this preferred embodiment is a
portion of the stabilizer 2300 that is configured with a surface
2303 that faces the base wall surface 2380, to prevent the
stabilizer from being pulled through bone as the cooperating bone
portion attempts to pull away from the spacer/cage 2200 during
normal movements of the patient. For purposes of the description
and claims herein, the surfaces 2303, 2380 are considered to be
"facing" over the extent to which they are cooperatively capable of
exerting a captive force on components therebetween. Essentially,
the convex surface 2303 faces the base wall surface 2380 at all
locations where the surface 2303 faces the plane within which the
surface 2380 resides. The cylindrical shape of the wall 2330
affords a substantial bone contact area and thus improves overall
stability without occupying a detrimentally large bone volume. The
surface 2380 does not have to be formed as part of a continuous
cylindrical surface as depicted, but is preferably convex where it
faces the base wall surface 2380. The convex portion preferably has
a radius at or adjacent the lengthwise central axis shown for the
cylindrical wall 2330. The cylindrical wall 2330 may alternatively
be an enlarged portion of the implant such as an elongated bulb or
cylinder and is configured to prevent pullout from the vertebrae
like the "T" shaped walls of the stabilizer spacer anchor 2370
prevent pullout from the channels 2255, 2265. The cylindrical shape
of the cylindrical wall 2330 is well suited to occupy the space
created by a drilled hole in the body of the vertebrae. This is
advantageous since drills are one of the tools of choice for
orthopedic surgeons since they perform well in narrow spaces, are
easy to control, and can be used to form bores quickly. The
cylindrical bore produced by drilling also is desirable from the
standpoint of avoiding crack propagation. The continuously curved
surface produced by boring does not have sharp corners or
intersections at which there may be stress concentration.
[0273] Of course, other than a cylindrical shape for the
wall/retaining member 2330 is contemplated. Other shapes, derivable
by those skilled in the art, may be utilized to prevent the
wall/retaining member from pulling through the bone. For example, a
"T"-shaped component could be utilized and has a more compact
shape. Further, a convex surface may be formed without a full
cylindrical shape.
[0274] The stabilizer cylindrical wall 2330 preferably has a
reduced lead-in portion to ease insertion of the stabilizer 2200
into the bone. This is illustrated in FIGS. 23A and 23B in the form
of a bullet tip-shaped nose 2361 with a tapered surface portion
angled between a leading end and the surface 2303. As the
stabilizer 2300 is advanced in its assembly path in the assembly
direction, the tapered surface portion bears against the bone
portion into which it is directed and progressively wedges that
bone portion towards the spacer 2200. The nose 2361 is part of
another reconfigurable body portion 2360. The reconfigurable body
portion 2361 prevents backout of the stabilizer 2300 from the bone
portion as well as preventing movement of the joined stabilizer and
spacer relative to the bone portions in the assembly/advancing
direction beyond the optimally identified location.
[0275] The reconfigurable body portion/nose 2361 is in the form of
an expandable bulb 2362 at the leading end of the stabilizer
cylindrical wall 2330. The reconfigurable body portion 2361 can
take other forms such as a series of self-retaining clips or barbs
deflected out into the bone. As illustrated in FIG. 23E and also in
a similar arrangement in FIG. 19, the expandable bulb 2362 has one
or more deflection gaps 2363 that bifurcate the reconfigurable nose
2361 into two or more parts. The deflection gap 2363 terminates at
a relief bore 2364. The relief bore 2364 is preferably circular to
minimize stress, thereby preventing material fracture. The material
between the outer surface of the cylindrical wall and the relief
bore defines hinged deflection walls 2365 that function as live
hinge portions. The deflection walls 2365 are the portions of the
bulb 2362 that undergo deformation, therein allowing separate
repositionable body tabs 2366 to deflect about the hinge portion
out to a diameter greater than that of the cylindrical wall 2330
and into bone, thereby retaining implant position. In the preferred
embodiment, the two tabs 2366 expand to a diameter approximately
30% greater than the cylindrical wall diameter.
[0276] FIG. 24A is an illustration of an implanted
spacer-stabilizer assembly 2401 with the tabs 2366 in the expanded
and locked positions. The stabilizer wall 2330 in FIG. 24A is in a
second position to which it has been moved, from a first position
prior to entry into the bone portion BP1, wherein the stabilizer
wall is aligned to initially enter the bone portion BP1. The
spacer/cage 2200 is secured in the intervertebral space between the
vertebral bodies 2410 (BP1), 2420 (BP2), with the spacer/cage 2200
and stabilizer in operative relationship with each other and the
bone portions/vertebral bodies 2410, 2420. In this state, parts of
each of the bone portion BP1 and the spacer 2200 are captive
between the facing surfaces 2303, 2380. A portion of the vertebral
body is cut away to illustrate the position of the stabilizers 2300
in the bone.
[0277] This stabilizer cylindrical wall 2330 has a central bore
2331 (FIG. 23A) terminating at, and contiguous with, the relief
bore 2364. The bore 2331 has a central axis A. A portion of this
bore, preferably at the trailing end, has threads 2332 or
alternative connection mechanism, such as a bayonet connection, to
securely contain a spreader 2421 (FIG. 24B) within the central bore
2331. The spreader 2421 has a diameter to occupy the central bore
2331 so that it will be guided in sliding movement therewithin.
along the axis A. At the trailing end of the spreader 2421 are
threads 2425, or other connection mechanism, to cooperate with the
threads/connection mechanism 2332, wherein the spreader 2421 is
pushed into and then advanced by threaded rotation into the bore
2331, as seen in the transition between FIGS. 25A and 25B. As an
outer surface of a tapered nose 2422 at the leading end of the
spreader 2421 abuts the internal surface of the tabs 2366 of the
reconfigurable stabilizer 2300, as seen in FIG. 25B, further
advancement of the spreader 2421 causes the reconfigurable body
tabs 2366 to deflect, with the upper tab 2366 in FIG. 25B deflected
outwardly into the surrounding bone, thereby securing the
stabilizer 2300 in place. The tabs 2366 are consistently fully
deflected when a shoulder stop 2426 abuts the stabilizer proximal
face 2321 and the internal surfaces of the tabs 2366 rest on a
shaft face 2423.
[0278] Located at the proximal/trailing end of the spreader 2421 is
a drive head 2429 which in this embodiment is a drive pocket 2427
with a regular array of drive faces 2424 thereon. The pocket 2427
is configured to receive and intermesh with drive faces 2434 on a
drive head 2433 of a spreader driver 2430 (FIGS. 24C and 24D) such
that turning of the spreader driver 2430 through a hand-graspable
driver handle 2431 will advance spreader 2421 into the stabilizer
2300 for locking. The leading end of the drive head 2433 may be
configured for eased insertion into the drive pocket 2427 by using
a taper 2432, radius, or other means and may also have a shoulder
2435 to block insertion consistently at a preferred depth.
[0279] To prevent unintended separation of the spreader driver 2430
from the spreader 2421, the drive head 2433 may incorporate an
anti-separation feature. For example, in this embodiment the drive
head 2433 may be bifurcated one or more times to create
repositionable arms 2437 separated by one or more deflection gaps
2436. It is preferred that the arms 2437 elastically spring out to
create an outside diameter of drive head 2433 that is slightly
larger than that of the drive pocket 2427 so that, when inserted, a
frictional fit of the drive head 2433 within the drive pocket 2427
is created with the arms 2437 wedged towards each other, wherein
the spreader 2421 is not prone to unintentionally falling off yet
is easily released when needed by the surgeon by intentional
retraction of the spreader driver 2430. The spreader driver may
include one or more alignment faces 2438 as illustrated in FIG. 24D
to assist centering in the drill guide cylinder. In addition,
handle 2431 may assume other hand fitting profiles such as a
teardrop.
[0280] Different forms of instruments usable to install
spacer/stabilizer assemblies into the affected intervertebral
spaces are described below.
[0281] One embodiment of a spacer/cage inserter tool is shown at
2600 in FIG. 26A-28B. The tool 2600 is attached to the spacer body
2290 at an instrument attachment portion 2208 of the implant
spacer/cage 2200. The inserter tool 2600 has a connection tip
portion 2640 at the distal end of a guide bar body 2630 which, in
this embodiment, is in the form of a threaded prong 2632 and a
non-threaded prong 2631 for engagement in the threaded attachment
holes 2215a, 2215b in the implant body 2290. The non-threaded prong
2631 resides in the one of the instrument attachment holes 2215a,
2215b of the implant spacer/cage 2200 that may be unthreaded. As
noted above, the holes/bores 2215a, 2215b are both shown to be
threaded, for reasons stated. However, one hole may be unthreaded.
The threaded prong 2632 threads into the other, threaded hole
2215a, 2215b and holds the implant spacer/cage 2200 tight to an
inserter face 2633. Together, both prongs 2631, 2632 serve to
maintain consistent alignment of the spacer inserter instrument
2600 with the implant body 2290 thereby controlling the implant
spacer 2200 during insertion. The connection tip 2640 portion may
take other forms such as a bayonet connection or clamping arms. The
instrument attachment portion 2208 is configured accordingly with a
complementary structure.
[0282] The guide bar body 2630 (FIG. 26A) has a handle portion 2620
for user control over the inserter tool 2600. This handle 2620 has
a graspable length that is preferably oriented to be angled, in one
form on the order of 90 degree, to the central axis of the body
2630. The guide bar body 2630 houses a locking shaft 2614
illustrated in FIG. 26B. A threading spool 2611, here illustrated
as an enlarged portion of the shaft is used to turn the locking
shaft 2614, which terminates at the threaded prong 2632. As the
threading spool 2611 is hand rotated, the threaded prong 2632 seats
into one of the threaded attachment holes 2215a, 2215b on the
implant, therein securing the implant spacer/cage 2200 to the
inserter tool 2600.
[0283] The surgeon may then grasp the handle 2620 and guide bar
body 2630 to control insertion of the spacer/cage 2200 into the
intervertebral space. The nose 2400 of the implant spacer/cage 2200
is guided into a predetermined position between the vertebral
endplates. The surgeon may choose to tap an impact fitting 2610
with a hammer to assist driving the implant spacer/cage 2200 into
the intervertebral space. This impact force is transmitted from a
transmission face 2613 to the adjacent face of the guide bar body
2630 then through inserter face 2633 to the spacer proximal face
2240. The proximal end of locking shaft 2614 may include a collar
2636 for engagement with an extended handle thereby providing the
user greater control over the shaft.
[0284] The guide bar body 2630 may have one or more access
apertures 2634 to facilitate viewing and/or cleaning. The length of
the guide bar body 2630 is preferred to extend long enough that the
handle 2620 can be grasped a comfortable distance outside of the
patient's skin. The distal portions of the inserter tool 2600 are
sized to pass through the internal channel formed by a tissue
retractor.
[0285] The guide bar body 2630 may also cooperate with an accessory
guide holder 2650, shown in FIGS. 26C and 26D, secured on or
integrated into the outer surface of the body 2630 to hold and
guide accessories/tools such as drill bits and drivers used in
conjunction with the inserter 2600. The guide holder 2650 may have
one or more accessory retainer portions 2660, with each of the two
shown in the form of a spring-biased locking arm 2661. Each locking
arm 2661 may have a resilient body integral with a main frame 2659
on the guide holder 2650 that springs toward a locking face 2663.
This version is not shown in the drawings. FIGS. 26C and 26D
illustrate, as a preferred alternative, a rigid locking arm 2661
movable about a pivot pin 2665. In a pivot gap 2666, a space is
provided for a compression spring, or other biasing component 2662,
to bias the locking arm 2661 in the direction of the arrow A to
reposition the locking face 2663 thereon.
[0286] The accessory guide holder 2650 has a proximal face 2668 and
a distal face 2667. Situated, preferably on at least the proximal
face 2668, is an accessory positioner 2664 shown here in the form
of a recess/aperture. In this embodiment, multiple, additional
positioning recesses 2669 are provided. Some of the positioning
recesses 2669 are shown as full, or blind, bores located different
distances from the central axis of the guide bar aperture 2664 to
reflect positioning required by accessories to be attached.
[0287] Illustrated in FIGS. 27A-27G are various exemplary
instruments/components including a drill guide-drill assembly 2700,
as shown in FIG. 27H. In one preferred form, the drill guide 2700
is interconnected with the spacer inserter tool 2600 to create an
interdependent assembly that will improve stability of the drill
guide 2700 and accuracy in placement of the spacer/cage 2200. This
combined drill guide-spacer inserter assembly is shown at 2790 in
FIG. 27G. It is possible, although less preferred, that the spacer
inserter tool 2600 and the drill guide-drill assembly 2700 are not
interconnected. In this configuration, the drill guide 2700 may
have its own handle 2711 depending from a proximal end. FIG. 27H
illustrates the drill guide-drill assembly 2700 without the spacer
insert tool 2600.
[0288] A preferred embodiment of the drill guide 2700 is
illustrated in FIGS. 27A-27C. A drill guide body 2705 spans between
a drill guide tip 2703 and a drill guide shoulder 2702. The drill
guide body 2705 has an outer drill guide wall 2706, which in this
case defines a drill guide cylinder 2701 to receive and guide a
drill 2720 as shown in FIG. 27D. Although the wall 2706 is
illustrated as a continuous cylinder, the wall 2706 may be
discontinuous. For example, the wall 2706 may be in the form of a
plurality of tabs extending from the drill guide body 2705 yet
still functioning to contain and guide the drill 2720. Preferably
at the proximal end of the drill guide body 2705, although it could
be positioned elsewhere, the drill guide shoulder 2702 is provided.
This shoulder 2702 interfaces with a drill guide stop 2722 on the
drill 2720 to stop penetration of the drill 2720 into the bone at a
predetermined depth. Also, preferably at the proximal end of the
drill guide body 2705 is a positioner 2707 shaped to complement the
accessory positioner 2664 on the accessory guide holder 2650. The
positioner 2707 in this embodiment is in the form of a positioning
boss 2708 configured to fit in one of the positioning recesses
2669.
[0289] The distally located tip 2703, seen clearly in FIGS. 27A and
27C, is configured in profile and size to complement the spacer's
stabilizer anchor 2245, in this case to be slid into one of the
spacer channels 2255, 2265 with which it has a complementary shape.
The tip 2703 has a "T"-shaped configuration much like the
stabilizer's spacer anchor 2370 in FIG. 23A. Similarly, the drill
guide tip 2703 has a flat track or base wall 2712, a web wall 2710,
and a base nose 2709. The base nose 2709 is tapered and radiused
much like the stabilizer base wall nose 2311 to simplify insertion
into one of the channels 2255, 2265. The web wall 2710 extends
upright from the base wall 2712 and is integrated into, or
otherwise attached to, the drill guide body 2705. The tip 2703 also
has a drill guide stop 2704, here in the form of a ridge extending
out from the web wall 2710, to limit overinsertion once the stop
2704 abuts the proximal face 2240.
[0290] In a preferred embodiment, as shown most clearly in FIG.
27D, the drill 2720 has an elongate body 2729 with several features
thereon. The proximal end of the drill 2720 has a drive shaft 2728
with drive faces 2723 thereon defining a polygonal outer drive
surface. The drive faces 2723 are configured to be directed into a
complementary shaped receptacle on the handle 2711. Alternatively,
the drive shaft could be configured in the shape of a handle. The
drill stop 2722 is configured in this case to abut the drill guide
shoulder 2702 when the drill 2720 has reached its predetermined
depth. The body 2729 may also include one or more radially
enlarged, cylindrical alignment faces. This embodiment has a
proximal alignment face 2726 and a distal alignment face 2727. When
the drill body 2729 is situated within the drill guide wall 2706,
these alignment faces 2726, 2727 are sized to have a diameter
slightly less than the inner diameter of the drill guide cylinder
2701 to maintain alignment and minimize wobble of the drill 2720
during use. A base region 2725 is a recessed area in the body which
may be configured to separate the alignment faces 2726, 2727 and
for collection of bone chips as the drill 2720 engages with and
removes bone. In other embodiments, this collection recess 2731 may
be directly adjacent cutting flutes 2724 as shown in the partial
view of FIG. 27D. At the distal end of the drill 2720 is a cutting
tip 2721 which is preferably tapered back to engage the bone from a
starting point. Cutting flutes 2724 extend back helically from the
tip 2721 to carry bone chips away from the cutting tip 2721. The
flutes 2724 and tip 2721 have sharp cutting faces 2730 on edges
thereon to ease cutting through bone.
[0291] FIG. 27E is a close-up view of the proximal end of the drill
guide-spacer inserter assembly 2790 of FIG. 27G. As the drill guide
tip 2703 is inserted and translated into one of the channels 2255,
2265, the stop 2707 of the drill guide 2700 will approach the
accessory positioner 2664. For this embodiment, the leading end of
the positioning boss 2708 will align with a predetermined
positioning recess 2669 and eventually be moved therein. As the
leading end of the drill guide shoulder 2702 contacts the sloped
entry face 2671 of the locking arm 2661, the locking arm 2661 will
be cammed back until the trailing face of the drill guide shoulder
2702 passes and then is captured by the locking face 2663 once the
locking arm 2661 springs back into position. In this state, the
drill guide tip 2703 is fully seated in a channel 2255, 2265 and
the drill guide stop 2704 abuts the proximal face 2240 of the
spacer/cage 2200. The drill guide 2700 is thus fully docked to the
spacer inserter tool 2600.
[0292] Tools to measure the anatomical void where a spacer will be
placed may be used to determine correct spacer size. For example,
trial spacer 3300 (FIG. 38A) comprises a trial insert 3302. The
trial insert 3302 comes in various sizes and are generally the same
shape of the implants offered. The surgeon slips various trial
inserts in the void until an appropriate size is determined. The
trial spacer includes a trial rod 3303, a trial handle 3301 for
controlling the trial spacer 3300 within the surgical corridor, and
a pod 3304 for connection purposes or for tapping with a surgical
hammer. In some cases an extension handle, such as illustrated in
FIG. 38B, may be utilized to extend the reach of an instrument. It
includes a grip portion 3400 and a pod clasp 3401 which may be used
for example to slide over and connect with the handle of another
instrument by way of pod 3304. Clasp 3401 may include a retention
mechanism, here illustrated in the form of a ball detent.
[0293] The surgical technique begins by preparing the patient using
standard pre-op procedures. The patient is positioned on the
operating room table consistent with the surgical approach required
to gain disc space access. For example, the spacer illustrated in
FIG. 9 is adapted best for an anterior surgical approach wherein
the patient would be positioned supine on the operating table for
an ALIF procedure. A surgical technique for a lateral approach is
described below, as the spacer-stabilizer assembly of FIG. 24A is
well suited to be inserted laterally. Clearly, the surgical
technique can be easily adapted for other approaches.
[0294] For the lateral approach, the patient is typically
positioned sidelying on the contralateral side of the incision
site. EMG monitoring may be useful during surgery to help the
surgeon steer clear of nerves near the surgical path.
[0295] Incisions from the lateral side, to open access to the
surgical site, are made. Tissue dilators and/or retractor systems
may be used to access the affected disc space along with access
lighting. Using instruments such as shavers, curettes, and
rongeurs, the diseased disc material is removed and the endplates
are prepared and roughened to expose bleeding bone. Disc space
sizing instruments, such as trial spacers and/or imaging, may be
used to correctly size the spacer/cage 2200 and stabilizers 2300
required for the patient. The spacers and stabilizers may be
provided in one or more surgical kits in a variety of sizes to suit
the patient's anatomy along with instruments described above. This
sizing may include not only measuring the gap between endplates,
but also angles between the endplates, and the overall footprint
size of the endplates.
[0296] The dimensions of the spacers 2200 of this embodiment will
generally range from 7 mm to 17 mm in height (h), between 35 mm and
65 mm in length (L), and 11 mm to 21 mm in width (W). The angle
between the superior and inferior endplate facing surfaces of the
spacer generally ranges from 0-12 degrees.
[0297] The selected spacer is chosen from the surgical kit and just
before or after attachment to the spacer inserter tool 2600 (as
previously described), the spacer opening 2232 may be packed with a
chosen graft material. The inserter tool 2600 with the selected
spacer attached is then guided through the incision, down the
corridor created by the retractor, until it has reached its
predetermined position in the intervertebral space. The placement
of the implant may be checked by imaging and readjusted. Markers
placed in the marker housings 2285 will show on imaging therein,
assisting the surgeon in properly positioning the spacer. Unless
preassembled, the tip 2703 of the drill guide 2700 is then guided
along the guide bar body 2630 of the spacer inserter tool 2600 and
directed into one of the channels/tracks 2255, 2265 of the
spacer/cage 2200. The drill guide 2700 is translated until the
drill guide 2700 abuts against the spacer/cage 2200 and/or the
drill guide shoulder 2702 is captured under the locking face 2663.
The drill guide tip 2703 is preferably configured in a "T" shape
sized to easily slide into the spacer's channel 2255, 2265 with
minimal play.
[0298] A drill 2720 of predetermined diameter is inserted into the
cylinder 2701 of the drill guide 2700. The surgeon, utilizing hand
force or power on the drive faces 2723, creates a bore/channel into
the wall of the vertebrae by advancing the drill 2720 into the
drill guide cylinder 2701 and vertebral body until the drill stop
2722 on the drill 2720 abuts the drill guide shoulder 2702,
indicating that the full predetermined depth of the drill has been
reached. The drill 2720 and guide 2700 are then removed. Locking
the drill guide 2700 to the channel/keel track 2255, 2265 assures
precise control over the starter hole position and angulation
therein, assuring easy insertion of the stabilizer cylindrical wall
2330 later.
[0299] The stabilizer 2300 is now attached to a stabilizer inserter
2800, illustrated in FIGS. 28A and 28B. The stabilizer inserter
2800 has an elongate tube or shaft body 2801 with an insertion tip
2802 at a leading end. The insertion tip 2802 has a reduced
diameter leading prong 2803 sized to occupy the central bore 2331
of the stabilizer cylindrical wall 2330. The prong 2803 assists to
control the stabilizer 2300 during insertion. Stepped back from the
prong 2803 is a threaded section 2804 of the insert 2800 configured
to engage the internal threads 2332 of the stabilizer bore 2331. A
stop 2805 abuts the proximal face 2321 of the stabilizer 2300 when
the inserter 2800 is fully advanced and seated in the stabilizer
2300. The trailing end of the stabilizer inserter 2800 has an
impact surface 2807 for tapping the stabilizer 2300 into position.
A graspable handle 2806, in a preferred embodiment, has an enlarged
tip 2809 upon which the surface 2807 is defined and which will
contact the impact face 2612 of the spacer/cage inserter tool when
the stabilizer is fully seated thereby preventing over penetration
of the stabilizer 2300.
[0300] Utilizing the handle 2806 of the stabilizer inserter
instrument 2800 to steer and advance down the retracted surgical
corridor, the base nose 2311 at the leading end of the stabilizer
is inserted into a keel track channel 2255, 2265 and advanced in a
first direction in a linear path by the surgeon, tapping at the
trailing end of the stabilizer inserter instrument 2800 into the
vertebrae until the stabilizer 2300 reaches the stabilizer stop
2276 and achieves an operative relationship with the spacer 2200.
As the stabilizer is advanced, the leading edge 2340 cuts through
the bone portion between the drilled bore/channel and the adjacent
surface on the bone portion. Alternatively, a complementary slot
for receiving the web 2320 can be pre-formed in the bone portion,
making the sharp leading edge 2340 potentially unnecessary. Even if
this slot is pre-formed, the sharp leading edge 2340 may still
perform a valuable function in aligning/guiding the web 2320 at the
slot. The self-retaining tabs/barbs 2350 will prevent backout of
the stabilizer 2300 from the spacer channels 2255, 2265. The
stabilizer inserter 2800 is then unthreaded from the stabilizer
2300 and removed.
[0301] A threaded spreader 2421, as shown in FIG. 24B, is then
attached to the spreader driver 2430 in a first position and
advanced by being turned around its lengthwise axis into the
stabilizer 2300 central bore 2331 into a second position, wherein
the spreader is fully seated. FIG. 25B illustrates a spacer/cage
2200 with a stabilizer 2300 inserted therein. The spreader 2421 is
partially seated within the stabilizer 2300 wherein the nose 2422
of the spreader 2421 begins contact with the internal surface of
the stabilizer tabs 2366, as shown in FIG. 25B. FIG. 25A is a
similar illustration, but the spreader 2421 has yet to contact tabs
2366. A portion of the stabilizer is resected for viewing
purposes.
[0302] The reconfigurable stabilizer 2300 is fully secured when the
spreader 2421 is fully seated, and changed from this first state by
causing tabs 2366 to be deflected from a first relaxed position
into a second position and forcibly into the surrounding bone,
representing a locked state for the stabilizer. The bone-engaging
tabs 2366 produce a localized compression that reconfigures the
adjacent bone so as to further enhance compression between that
bone portion and the spacer. The spacer stabilizer assembly 2400,
situated within the partially resected vertebrae and with
stabilizer tabs 2366 fully deployed, is illustrated in FIG. 24A.
The spreader driver 2430 may now be removed. Following the steps
above, bores for other stabilizers can be drilled and other
stabilizers can be inserted and locked into position in like manner
to engage both bone portions 2412, 2413. The spacer inserter tool
2600 is then removed. The wound closure procedure may then be
initiated. The instrumentation preferably functions by movement
along an axis/line coincident with the implant insertion axis,
thereby minimizing the incision size.
[0303] The joined spacer/cage 2200 and stabilizer 2300 implant may
be removed by unscrewing and therein unlocking the spreader(s) 2421
and removing it. The spacer/cage 2200 and stabilizer 2300 implant
can then be removed by reattaching the inserter tool 2600 and
pulling opposite to the path/line of insertion. If necessary, the
stabilizer 2300 may be backed out from the channels/tracks 2255,
2265 by shearing the spacer track material, thereby releasing the
tabs/barbs 2350.
[0304] Insertion and removal of the spacer and stabilizer is
affected by movement of those components in a single plane, and in
a preferred form in parallel lines, whereby the overall procedure
is minimally invasive.
[0305] One or more surgical kits may be provided containing all
implants and instruments required to perform the surgery. These
kits may include implants such as various sized spacers,
stabilizers, and spreaders. They may also include instruments that
directly interface with these implants such as spreader drivers,
spacer inserter tools, stabilizer inserters and drill guides. In
addition, the kits may contain scalpels, drills, guide wires,
dilators, retractors, lighting sources, and instruments for disc
preparation such as shavers, curettes, and rongeurs. A kit
containing a nerve monitoring system may also be provided.
[0306] In the preferred embodiment, the distance from the central
axis of the drilled hole in the vertebral bodies to the nearest
spacer opposing surface is on the order of 0.5 mm greater than the
distance between the central axis of the stabilizer cylindrical
wall and the nearest spacer opposing surface that produces a
captive force. In other words, the first surface 2380 of the base
wall 2310 is spaced from the axis A of the wall 2330 a distance
that is less than the distance between the surface 2266 bounding
the channel 2255 and the central axis of the drilled bore/channel
in the bone portion. This discrepancy in distance causes there to
be approximately 0.5 mm movement that preferably causes compression
of parts of the spacer and bone portion between the cylindrical
wall surface 2303 and the opposing surface 2380 that is
progressively developed as the spacer and stabilizer are moved from
their pre-assembly relationship into their operative relationship.
This compression force resulting from the cooperative interaction
of the stabilizer, bone portion, and spacer, as the spacer and
stabilizer are placed into operative relationship with each other
and the bone portion, assures that the vertebral body/bone portion
is held tightly against the adjacent interbody/spacer surface,
therein, apart from imparting stability, improving the opportunity
for a successful fusion. Also, by keeping the cylindrical wall
relatively close to the endplate (approximately 5 mm above the
endplate), by applying a bearing force over a majority of the end
plate extent where the stabilizer overlies the same, the
cylindrical wall is securely kept in the hard endplate bone. If the
cylindrical wall is too deep into the vertebrae (web wall is too
tall), the cylindrical wall will reside in the softer bone of the
vertebral body and therein is more likely to deform the softer
bone, potentially allowing the implant to loosen.
[0307] Biomechanical testing of the spacer stabilizer assembly 2400
revealed static torsion of 36 Newton Meters with 9 degrees
rotation. This is roughly triple the results of a pedicle screw
corpectomy model. Other performance measures of this assembly
include static yield compression of 4190 Newtons, and an ultimate
compression strength of 4798 Newtons. Stability was demonstrated in
all planes of movement. This positive fixation results
instantaneously and is only further enhanced by eventual bone
ingrowth.
[0308] The bodies 2290 of the spacers in these embodiments are
preferably manufactured using biocompatible polymer such as PEEK
(polyetheretherketone) or similar materials, but could be made
using metals such as titanium or titanium alloys such as Ti64, or
stainless steel alloys, or other biocompatible materials. The
stabilizer is preferably manufactured using these metals although
strong polymers or composites are also usable. Materials discussed
and disclosed earlier may also be used. The implant may utilize
coatings such as hydroxyapatite or other surface treatments to
assist surface bone adhesion to the implant.
[0309] The spacer is shown with a symmetrical configuration for
insertion selectively in either of opposite directions between
vertebrae and in an inverted orientation.
[0310] The spacer, such as the form illustrated in FIGS. 22A-22D,
and the stabilizer, such as the form illustrated in FIG. 23A, may
be inserted utilizing an alternative form of spacer/cage inserter
3000 illustrated in FIGS. 29-33. The inserter tool 3000 is attached
to the spacer body 2290 at an instrument attachment portion 2208 of
the implant spacer/cage 2200. The spacer inserter 3000 has a
connection tip portion 2640 at the distal end of a guide bar body
2630 which, in this embodiment, the connection tip portion is also
in the form of a threaded prong 2632 and a non-threaded prong 2631
for engagement in the attachment holes of implant body 2290
illustrated in FIG. 22A as 2215a, 2215b. These holes/bores 2215a,
2215b are both shown to be threaded for reasons stated earlier
although one may be unthreaded. The non-threaded prong 2631 resides
in the one of the instrument attachment holes 2215a, 2215b of the
implant spacer/cage 2200 that may be unthreaded. The threaded prong
2632 threads into the other threaded hole 2215a, 2215b and holds
the implant spacer/cage 2200 tight to an inserter face 2633.
Together, both prongs 2631, 2632 serve to maintain consistent
alignment of the spacer inserter instrument 3000 with the implant
body 2290 thereby controlling the implant spacer 2200 during
insertion.
[0311] The connection tip 2640 portion may take other forms such as
a bayonet connection or clamping arms or non-circular boss end. The
instrument attachment portion 2208 is then configured with a
structure complementary to these other forms to impart control on
the spacer 2200.
[0312] The guide bar body 2630 may include a handle portion 2620
for user control over the inserter tool 3000. This handle 2620 has
a graspable length that is preferably oriented to be angled, in one
form on the order of 90 degrees to the central axis of the body
2630. In some embodiments, the handle portion may be extended
proximally on the guide bar body 2630 by stem section 2637 to
provide improved access. The guide bar body 2630 houses a locking
shaft 2614 (FIG. 26B) within a locking shaft aperture 3005 as
illustrated in FIG. 29. A threading spool 2611, sized and shaped
for finger advancement, is provided for the user to advance the
locking shaft 2614, which terminates at the threaded prong 2632 as
illustrated in FIG. 30 (threads not shown). One or more alignment
face 2635 may reside on locking shaft 2614 for alignment within the
guide bar body 2360. As the threading spool 2611 is hand rotated,
the threaded prong 2632 seats into one of the threaded attachment
holes 2215a, 2215b on the implant, therein securing the implant
spacer/cage 2200 to the inserter tool 3000. The non-threaded prong
2631 seats in the remaining attachment hole to prevent rotation of
the implant relative to the guide bar body.
[0313] The handle 2620 and guide bar body 2630 may be used by the
surgeon to control insertion of the spacer/cage 2200 into the
intervertebral space. The nose 2400 of the implant spacer/cage 2200
is guided into a predetermined position between the vertebral
endplates. An impact fitting 2610 on the proximal end of locking
shaft 2614 may be tapped with a hammer to assist driving the
implant spacer/cage 2200 into the intervertebral space. This impact
force is transmitted from a transmission face 2613 of locking shaft
2614 to the adjacent transmission face 3006 of the guide bar body
2630 then through inserter face 2633 to the spacer proximal face
2240.
[0314] The guide bar body 2630 may have one or more access
apertures 2634 along the length of body 2630 to facilitate viewing
and/or cleaning. The length of the guide bar body 2630 is preferred
to be of sufficient length wherein an attached handle 2620 can be
grasped a comfortable distance outside of the incision above the
patient's skin. The distal portions of the inserter tool 3000 are
sized to pass through the internal channel formed by a tissue
retractor or surgical tube.
[0315] The guide bar body 2630 illustrated in assembly in FIG. 29,
includes a longitudinal guide 3001 illustrated in FIG. 31 in the
form of opposing T-shaped channels 3002 and 3003. The T-shaped
channels 3002, 3003 are defined by guide walls 3007 with guide
surfaces 3008 on each guide wall 3007. The profile of the T-shape
may vary in width along the length of the channel and entry into
the channels from a proximal or distal end may be sloped to provide
eased entry into or out of the channel by other implant or
instrument parts. Channels 3002 and 3003 are preferably configured
of similar profile and dimension and align with spacer channels
2255 and 2265 when inserter 3000 is secured to spacer 2200 as
illustrated in FIG. 29. FIG. 33 further illustrates the alignment
between channels in the instrument and implant. Like spacer
channels 2255 and 2265, it is preferred channels 3002 and 3003 are
configured to capture implant components and instruments for linear
sliding engagement down guide bar body 2360 and into spacer
channels 2255 and 2265 to assure alignment of additional implants
and instruments with the spacer and bone portions. For example, the
spacer anchor 2370 (FIG. 23A) of stabilizer 2300 may be inserted at
proximal channel face 3004 of inserter 3000 into channels 3002 and
3003. In this configuration, stabilizer 2300 and instruments such
as drill guides are guided from the entrance of the incision down
to their pre-determined location within the body therein avoiding
the challenges of aligning these structures deeper within the
incision site when surgical vision is compromised by surrounding
tissue. At the proximal end of the inserter body 2630 is inserter
transmission face 3006 positioned to transfer impact forces applied
by a hammer to impact fitting 2610, as well as fixation forces by
transmission face 2613 of locking shaft 2614 when locking spacer
2200 to inserter 3000. An elongated locking shaft aperture 3005
extends the length of guide bar body 2630 and is sized to house
locking shaft 2614. The shaft aperture is defined by shaft aperture
walls 3009 and shaft aperture surface 3010.
[0316] The accessory guide holder 2650, illustrated in FIGS. 26C
and 26D is unnecessary in this embodiment (FIG. 29) because the
longitudinal guide 3001 serves this function of holding and guiding
the stabilizer 2300 and other instruments from a proximal position
near the incision opening to predetermined surgical locations.
[0317] Illustrated in FIGS. 34-38 are exemplary instruments
configured for use with inserter tool 3000. One or more graft
blocks 3100 may be utilized to secure bone graft or other bone
substitutes within opening 2232 of spacer 2200 during insertion of
the spacer into the predetermined surgical space. In this
embodiment, the graft blocks 3100 are paired and are generally
mirror images of each other. Each graft block 3100 is configured to
enclose a graft opening of a spacer and therefore may assume other
shapes as required for this function. Here the graft blocks 3100
are in the form of generally rectangular shaped paddles 3101 with
containing face 3105 facing opening 2232 of spacer 2200. Paddle arm
3102 extends from paddle 3101 and terminates in handle 3103 for
grasping by surgeon. The handle portion may be enlarged and may be
knurled or include other textures to improve grip. At the distal
end of paddle 3101 is stop face 3104 for abutting bone or other
mechanical stops. One or more channel locks 3106 align the graft
block within the inserter tool 3000 and spacer 2200. In this
embodiment, the channel locks 3106 are in the form of opposing
alignment bosses 3110 shaped for capture and sliding engagement
within channels 3002 or 3003 of longitudinal guide 3001. Although
channel lock 3106 is illustrated here in the form of a T-shaped
complementary engagement, other shapes and forms may be assumed.
Channel lock 3106 may include a butt face 3111 to abut against a
stop on spacer to indicate proper paddle alignment over the graft
apertures.
[0318] Relief groove 3107 may be provided to assist sliding of
paddles 3101 along guide bar body 2630 and to provide deflection of
paddle 3101 to accommodate various sizes of spacers 2200. Spacing
wall 3108 distances paddle 3101 a predetermined distance from
axis-B sufficient for paddle to cover the graft opening. Bottom
paddle surface 3109 glides along bottom surface of channel 3002 or
3003.
[0319] Illustrated in FIGS. 36-38 is drill guide 3200 configured
for compatibility with inserter 3000 wherein drill guide 3200 is an
alternative to drill guide 2700. During portions of surgery, drill
guide 3200 is interconnected with the longitudinal guide 3001 of
the spacer inserter tool 3000. This relationship assures the drill
guide 3200 is held stable in the incision and accurately positioned
on a predetermined bone portion site for drilling of a stabilizer
hole. This combined drill guide-spacer inserter assembly is
illustrated in FIG. 49-51.
[0320] Drill guide body 2705 (FIG. 36, 37A, 37B) spans between a
drill guide tip 2703 and a drill guide shoulder 2702. The drill
guide body 2705 has a drill guide wall 2706, the face of which in
this case defines a drill guide cylinder 2701 to receive and guide
a drill 2720 such as shown in FIG. 27D. Although the wall 2706 is
illustrated as a continuous cylinder, the wall 2706 may be
discontinuous. For example, the wall 2706 may be in the form of a
plurality of tabs extending from the drill guide body 2705 yet
still functioning to contain and guide the drill 2720. Preferably
at the proximal end of the drill guide body 2705, although it could
be positioned elsewhere, the drill guide shoulder 2702 is provided.
This shoulder 2702 interfaces with a drill guide stop 2722 on the
drill 2720 to stop penetration of the drill 2720 into the bone at a
predetermined depth. The drill exits the distal cylinder face 3201
before engaging the vertebral body.
[0321] Tip 2703 (FIG. 36, 38) of this embodiment is distally
located on drill guide body 2705 comprising similar features
illustrated in FIG. 27C. As illustrated in FIG. 36, tip 2703 is
configured in profile and size to fit within inserter channels 3002
and 3003 as well as spacer channels 2255, 2265. The drill guide tip
2703 of drill guide 3200 comprises a flat track or base wall 2712,
a web wall 2710, and a base nose 2709. The base nose 2709 is
tapered and radiused much like the stabilizer nose 2311 to simplify
insertion into one of the channels 3002, 3003. The web wall 2710
extends upright from the base wall 2712 and is integrated into, or
otherwise attached to, the drill guide body 2705, however in this
embodiment, although not necessary, the web wall extends
substantially the entire length of guide body 2705 parallel to
axis-C. A drill guide stop 2704 is located near the proximal end of
body 2705 at web wall 2710 and is in the form of a ridge extending
out from the web wall 2710. Drill guide stop 2704 limits
overinsertion of the drill guide once the stop 2704 abuts proximal
channel surface 3004.
[0322] A bone drill, such as the one illustrated in FIG. 27D is
compatible with drill guide 3200.
[0323] In view of the surgical technique described earlier, minor
modifications to the technique are made when substituting tools
such as inserter tool 3000, graft blocks 3100, and drill guide
3200. These surgical instruments as illustrated are also well
suited for a lateral surgery approach but may be adapted for other
surgical approaches.
[0324] Once again the technique begins by preparing the patient
using standard pre-op procedures and the patient is positioned on
the operating table laying with the lateral entry side facing
superiorly. EMG monitoring may be used to steer away from nerves.
Incisions from the lateral side to open access to the surgical site
are made. Tissue dilators and/or retractor systems may be used to
access the affected disc space along with access lighting. As
described previously, the diseased disc material is removed and
endplates are prepared.
[0325] Trial spacers, such as the one illustrated in FIG. 38A may
be used to correctly size the spacer and stabilizer required for
the patent. When needed, extension handles such as the one
illustrated in FIG. 38B may be serially attached to a distally
placed handle to increase extension length.
[0326] The selected spacer is chosen from the surgical kit and
secured to spacer inserter tool 3000 by advancing locking shaft as
previously described. A graft block 3100 is chosen (FIG. 39-40),
and with stop face 3104 facing distal, channel locks 3106 are
inserted at the proximal channel surface 3004 of inserter 3000 into
the appropriate T-shaped channel 3002 or 3003 and advanced distally
until containing face 3105 covers spacer graft opening 2232 as
illustrated in FIG. 41. Interference between alignment bosses 3110
on the graft block and portions of the inserter or spacer are
utilized in some embodiments to stop the graft block at a
predetermined position over the graft opening.
[0327] Holding the assembly so the unblocked spacer opening 2232 is
facing up (FIG. 42) so that gravity can assist, the spacer opening
2232 may be packed with a chosen graft material.
[0328] If the surgeon chooses, the second graft block 3100 is
chosen with channel locks 3106 again inserted at the proximal
channel surface 3004 of inserter 3000 into the available channel
3002 or 3003 (FIG. 43), and advanced distally wherein containing
face 3105 covers spacer opening 2232. The graft should now be
contained by the walls of the spacer and each graft block
containing face 3105 (FIG. 44).
[0329] The inserter tool with the selected spacer attached is then
guided through the incision, down the corridor created by the
retractor (not shown), with the leading end of the spacer wedging
between the vertebral endplates (FIG. 45) and stop face 3104 of
graft block 3100 abutting cortical bone wall of vertebral bodies
VB1, VB2. As the spacer is advanced in the intervertebral space
IVS, graft blocks 3100 are forced proximally (FIG. 46) until spacer
has reached its predetermined position in the intervertebral space
(FIG. 47). The graft blocks 3100 may now be removed from the
surgical corridor by retracting them proximally (FIG. 48).
[0330] The tip 2703 of drill guide 3200 is then inserted into one
of channels 3002 or 3003 (FIG. 49) and advanced distally until
proximal channel surface 3004 abuts drill guide stop 2704 (FIG.
50-51). The tip 2703 is now engaged within one of the spacer
channels/tracks 2255, 2265 of the spacer/cage 2200 assuring correct
drill position with respect to the spacer.
[0331] A drill 2720 of predetermined diameter for chosen stabilizer
is inserted into the cylinder 2701 of the drill guide 3200 creating
a bore into the wall of the vertebrae by advancing the drill 2720
by hand or power into the drill guide cylinder until the drill stop
2722 abuts drill guide shoulder 2702 indicating the drill has
reached a predetermined depth suitable for the stabilizer. The
drill 2720 and guide 3200 are then removed. The procedure is
duplicated on the opposing side to create a similar bore. The drill
and guide are again removed. (As an alternative, the surgeon may
opt to place a stabilizer 2300 in position within the 1.sub.st
drilled hole in the vertebral body before moving on to drill in the
opposing vertebrae).
[0332] The selected stabilizer 2300 is now attached to a stabilizer
inserter 2800 illustrated in FIGS. 28A and 28B by inserting the
inserter's prong 2803 of insertion tip 2802 into the central bore
2331 of stabilizer 2300 and intermeshing with threads 2332. The
base nose 2311 at the leading end of the stabilizer is then
inserted into channel 3002 or 3003 of inserter tool 3000 (FIG. 52)
and stabilizer 2300 is advanced into the bore created in the
vertebrae until the stabilizer 2300 reaches the stabilizer stop
2276 and achieves an operative relationship with the spacer 2200
(FIG. 53). The stabilizer inserter 2800 is removed.
[0333] The drill guide 3200 is reinserted into the longitudinal
guide 3001 and fully advanced (FIG. 54). A threaded spreader 2421
(FIG. 24B) attached to the spreader driver 2430 is advanced down
drill guide 3200 and threaded into stabilizer threads 2332 until
spreader 2421 is fully seated within stabilizer representing a
locked state for the stabilizer 2300 (FIG. 56). The spreader driver
2430 and drill guide 3200 may now be removed and the procedure
repeated on the opposing side until spacer 2200 and stabilizers
2300 are fully secured.
[0334] The spacer inserter tool 3000 and all instrumentation are
removed and wound closure procedure may then be initiated.
[0335] Discussion of Alternatives
[0336] The device disclosed may be used in a variety of locations
in the body--wherever there is a need to secure an implant to bone
or bone fragments. For example, the device may be configured to
secure the stemmed tibial plate in a total knee replacement
surgery. The device is also well suited for stabilizing the sacral
iliac joint. Other possible bone portion fusions include: ankle and
subtalar fusions; MTP joint fusions of the great toe; opening wedge
high tibial and distal tibial osteotomies; and metacarpal hand
fusions. Spinal applications include cervical, thoracic and
lumbar.
[0337] In the preferred embodiment, the stabilizer deflection gap
is situated in a plane generally perpendicular to the web wall,
thereby minimizing forces which may cause the vertebral body to
crack. Alternatively other portions of the stabilizer cylindrical
wall could be configured to expand and retain position. For
example, the leading portion of the cylindrical wall could be
longitudinally gapped to expand in diameter.
[0338] The device may be used at adjacent vertebral levels. In the
preferred embodiment the cylindrical wall portion is kept near the
endplate thereby leaving an adequate amount of the vertebral body
bone between the adjacent level implants. Alternatively, the
channels/keel tracks 2255/2265 could be staggered on the implant,
thereby increasing distance between each stabilizer and thereby
maximizing bone mass therebetween.
[0339] As an alternative, the reconfigurable body portion of the
stabilizer can be deployed by a camming action rather than the
spreader utilized in the preferred embodiment. A cam situated at
the end of the spreader would deploy and lock the reconfigurable
body tabs upon rotation of the camming spreader.
[0340] As another alternative, the upper and lower stabilizers may
slidingly engage or otherwise interlock with each other, thereby
relieving some of the forces endured by the channels or keel/tracks
of the implant. Similarly, the upper and lower stabilizers may have
a continuous web wall joining them. For example, this web may have
a side lying flat track or base wall on the web to interconnect
into a stabilizer attachment such as a keel track on the side of
the implant body.
[0341] As another alternative, the implant body may be configured
with more than one stabilizer attachment site to accommodate a
plurality of stabilizers on one side. For example, the implant body
portion could be modified for keel tracks on both sides of the
graft portion. This configuration may be advantageous in an
interbody device for anterior surgical approach.
[0342] As another alternative, the web wall is manufactured
integral with the spacer and slides in with the implant wherein the
cylindrical wall portion slides over the web into pre-drilled holes
afterward.
[0343] Each of the described embodiments might be further modified
by additionally using screws, adhesives, or other supplementary
fixation structure.
[0344] Throughout, where there are cooperating components on
separate elements, it is contemplated that the described placement
of these components could be reversed. For example, the tabs/barbs
2350, shown on the stabilizers 2300, could be placed on the
spacer/cage 2200 with the complementary undercut regions 2225
provided on the stabilizer 2300. Different combinations and numbers
of these paired components can also be utilized.
[0345] Other mechanisms may be utilized to block the stabilizer in
its operative relationship with the spacer. For example, detent
arrangements, such as that utilizing a ball element, might be
substituted for, or used in conjunction with, the described
structure.
[0346] While the spacer is described above to be placed between
adjacent bone portions before the stabilizer is moved from a
pre-assembly relationship therewith into an operative relationship,
the stabilizer could be put in place first followed by placement of
the spacer. This is made possible through the use of a jig.
[0347] While assembly paths of all components are described as
linear, this is also not a requirement. Further, the assembly paths
for multiple stabilizers, while shown to be parallel, need not be
so oriented.
[0348] It is also contemplated that structures features from all
different embodiments are combinable in different combinations.
[0349] The foregoing disclosure of specific embodiments is intended
to be illustrative of the broad concepts comprehended by the
invention.
[0350] The foregoing invention has been described in accordance
with the relevant legal standards, thus the description is
exemplary rather than limiting in nature. Variations and
modifications to the disclosed embodiment may become apparent to
those skilled in the art and fall within the scope of the
invention.
* * * * *
References